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UNIVERSITY    OF    NEVADA 

BULLETIN  OF  THE  DEPARTMENT  OF 
GEOLOGY  AND  MINING. 


Vol.   1,  No.   1.  June.   1904, 


PRELIMINARY  REPORT 


ON  THE 


BUILDING  STONES  OF  NEVADA, 


INCLUDING  A  BRIEF  CHAPTER  ON 


ROAD  METAL. 


JOHN   A.  REID. 

1904.' 


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4vH/5%:*!}**2; 

-•      »  S  •*     *  %'  J>    ^  J*       »•»•> 


Table  of  Contents. 


CHAPTER  I. 

Introduction :  Need  for  knowledge  and  use  of  stone ;  uses  of 
rocks  ;  arrangement  of  context. 

CHAPTER  II. 

Rocks :  Their  nature  and  classification.  The  igneous  rocks ;  their 
occurrence  and  general  classification  : — plutonic,  intermediate, 
and  volcanic;  acid  and  basic.  The  tuffs;  the  atmospheric 
rocks,  eolian  and  aqueous,  including  sedimentary,  organic 
and  chemical  rocks.  The  metamorphic  rocks  with  their  divis- 
ions. 

CHAPTER  III. 

Qualities  of  building  stones.  Changes  in  rocks :  physical  and  chem- 
ical. Rock  characteristics :  color,  hardness,  strength,  structure, 
texture,  mineral  content.  Observations  on  rocks:  quarry, 
buildings,  chemical,  physical. 

CHAPTER  IV. 

Building  stones  of  Nevada :  Granites,  diorites,  rhyolites,  andesites, 
tuffs,  sandstones,  marbles,  travertine.  Characteristics,  uses, 
location  and  availability  of  each. 

CHAPTER  V. 

Road  Metal  and  some  General  Principles  of  Road  Making.  Agents 
destructive  of  roads ;  selection  of  materials  to  withstand  these ; 
kinds  of  roads  for  different  traffic  requirements.  Necessary 
qualities  in  road  metal.  Materials  available  in  Nevada.  List 
of  references  on  the  subject. 

CHAPTER  VI. 

Conclusion:  Need  of  more  work  on  development  of  State  and  of 
more  exact  knowledge  regarding  the  resources. 


333114 


. 


INTRODUCTION. 

CHAPTER  I. 

The  statement  that  the  West  is  undeveloped  is  undeniably 
true.  It  is  doubly  true  of  the  State  of  Nevada.  Little  has  been 
done  to  develop  her  natural  resources  ;  little  is  known  of  the  bound- 
less wealth  of  her  mountains  and  valleys.  Yet  Nevada  is;  on  the 
eve  of  a  great  awakening ;  with  the  advent  of  irrigation  thousands 
of  acres  of  fertile  land,  now  desert  like,  will  be  made  to,  yield  an 
abundance  of  the  fruits  of  the  field,  and  will  support  a  la'ige  pop- 
ulation. As  the  community  increases  in  numbers,  a  demand  will 
arise  for  all  modern  improvements,  among  which  two  of  the  .most 
important  are,  permanent  buildings  and  good  roads.  It  is  needless 
to  state  that  both  of  these  are  made  possible  by  the  use,, of,, stone ; 
stone  for  erecting  substantial,  handsome  structures,  and  stone 
for  the  betterment  of  the  highways,  which  are  so  important  to  the 
healthy  life  of  a  growing  community.  It  is  not  needless,  however, 
to  state  that  the  principle  underlying  the  choice  and  use  of  stone 
for  the  above  purposes  are  little  understood.  Moreover,  were 
these  principles  understood,  little  is  known  of  the  various  rocks 
in  the  state  available  at  present.  The  purpose  of  this  preliminary 
report,  then,  is  as  follows :  First,  to  present  the  main  principles 
governing  the  selection  and  use  of  building  stones  and  road  metal ; 
second,  to  describe  briefly  the  stones  now  in  use,  or  that  can  easily 
be  used,  in  Nevada, -with  their  location  and  availability;  and  third, 
to  attempt  to  arouse  a  larger  interest  in  a  subject  of  sucjh  vast 
importance  to  a  healthy  commonwealth, 

We  in  the  West  are  prone  to  build  for  the  day  only ; :  tomor- 
row is  allowed  to  care  for  itself.  This  is  undoubtedly  ^cheaper  at 
any  particular  time,  but  is  far  dearer  in  the  end.  The  scale  ;of  any 
civilization  may  be  told  from  its  architecture ;  the  stability  of  that 
civilization  is  shown  by  the  materials  used  in  the  architecture, 
lint  we  are  learning  to  build,  not  for  mere  decades,  but  for  cen- 
turies of  use,  and  to  do  this  we  must  use  stone.  The  first  cost 
may  be  high,  but  the  ultimate  expense  is  low.  The  result  ^of  this 
is  to  be  seen  now  in  many  places.  Not  only  are  stone  buildings 
more  common,  but  also  the  use  of  stone  is  seen  in  bridges,  cul- 
verts, roads,  curbing,  and  in  many  other  ways  too  numerous  to 
mention.  In  a  rapidly  growing  state  like  Nevada  the  importance 
of  these  considerations  cannot  easily  be  overestimated,  yet  that 
importance  is  little  realized.  The  frontier  town  is  one  of  tents 


and  temporary  light  wooden  buildings.  Everything  is  done  with 
the  greatest  haste,  and  calculated  to  bring  in  the  largest  returns 
for  the  least  expenditure.  Every  western  town  has  gone  through 
such  a  period  in  its  growth.  After  this  first  newness  has  worn 
off  a  bit,  more  stable  conditions  obtain,  and  almost  imperceptably 
more  solid  and  substantial  structures  appear,  to  take  the  place  of 
the  first  flimsy  ones.  In  mountainous  regions  such  as  Nevada, 
men  have  turned  instinctivelv  to  the  rocks  in  the.  hills  for  build- 
ing materials.  As  a  consequence  nearly  all  of  the  towns  of  the 
state  show  one  or  more  stone  buildings,  while  in  the  larger  ones, 
as  Reno  and^  Virginia  City,  brick  is  common  also  as  a  material  of 
construction.  Yet  even  with  brick  structures,  stone  is  required  for 
cornices,  arches,  and  similar  uses.  The  people  need  to  know 
something  about  the  proper  and  improper  use  of  these  materials, 
which  of  course,  is  the  reason  for  the  writing  of  this  report. 

The  nature  of  this  subject  is  more  complex  than  appears  on 
casual  inspection.  Fundamental  principles  of  three  separate 
sciences  all  play  an  essential  part;  the  subject  is  built  upon  geol- 
ogy, physics  and  chemistry.  The  practical  man  may  believe  that 
he  has  no  time  for  such  considerations,  yet  the  simplest  rule  of 
thumb  method,  if  it  be  right,  is  founded  upon  true  scientific  prin- 
ciples. No  man  in  this  advancing  age  of  competition  can  afford 
to  be  ignorant  of  those  things  which  vitally  concern  him  and  his 
business.  Every  citizen,  directly  or  indirectly,  is  concerned  with 
the  erection  of  public  buildings,  private  buildings,  and  county  and 
city  highways.  Hampered  by  lack  of  facilities  for  detailed  work,  a 
full  report  on  the  subject  is  impossible  for  some  time,  yet  the  time  is 
ripe  for  a  little  knowledge  to  be  distributed  about  these  matters. 

The  chief  uses  of  rock  are  as  follows,  in  order  of  their  rel- 
ative importance.  First,  the  largest  amount  ot  stone  is  used  in 
the  construction  of  buildings,  under  conditions  already  mentioned. 
Second,  much  of  the  finest  grade  of  stone  is  used  for  monument- 
al and  ornamental  work.  It  is  not  right,  nor  is  it  necessary,  that 
nearly  all  of  oilr  rocks  for  such  uses  come  from  outside  localities. 
Third,  the  importance  of  crushed  rock  for  the  construction  of 
roads  is  well  known.  Fourth,  in  the  larger  towns  and  cities,  stone 
curbing  is  imperative  on  the  graded  streets.  Fifth,  the  use  of  cut 
stone  for  bridges  and  culverts,  especially  by  the  railroads,  is  grow- 
ing constantly.  Sixth,  much  cut  rock  is  used  for  sidewalks  and 
by  the  railroads.  Sixth,  much  cut  rock  is  used  for  sidewalks  and 
tiling  in  the  most  approved  buildings.  Besides  these,  there  are 
many  lesser  uses,  such  as  the  construction  of  piers,  break-waters, 
darns,  retaining  walls,  with  such  small  uses  as  hitching  posts, 


steps,  mounting  blocks,  and  the  like.    And  it  is  worth  noting  that 
this  list  is  constantly  increasing. 

The  text  will  be  divided  into  five  succeeding  chapters ;  a 
short  chapter  on  the  nature  of  the  various  rocks,  with  their  clas- 
sification;  a  second  chapter  devoted  to  the  qualities  of  building 
stones,  good  and  bad ;  a  third  devoted  to  an  account  and  descrip- 
tion of  the  building  stones  of  Nevada ;  fourth,  a  brief  chapter  on 
road  metal;  and  lastly  a  conclusion. 


CHAPTER  II. 

ROCKS  :    THEIR    NATURE   AND    CLASSIFICATION. 

To  the  average  man,  any  rock  is  either  a  granite,  a  porphyry, 
a  sandstone,  or  a  slate;  these  terms  are  all  embracing.  Were  it 
not  that  this  loose  use  of  terms  is  productive  of  actual  loss  in 
construction,  by  causing  a  misunderstanding  of  the  characteris- 
tics of  a  stone,  with  consequent  misuse,  this  chapter  would  be 
superfluous.  But  when  such  a  broad  error  is  made  as  the  use 
of  a  partially  decomposed  volcanic  rock,  an  andesite,  under  the 
belief  that  it  was  a  sandstone,  which  is  a  rock  not  often  subject 
to  decomposition,  at  least  in  the  better  grades,  the  writer  feels  it 
necessary  to  present  in  some  detail  the  various  types  of  rocks 
found  in  the  earth. 

The  first  question  naturally  arising  is  this :  What  is  a  rock  ? 
A  proper  definition  is  as  follows :  A  rock  is  any  material  making 
up  an  integral  part  of  the  earth ;  that  is,  any  substance  which  ex- 
ists in  large  enough  amount  to  be  considered  as  constituting  an 
essential  portion  of  the  globe.  This  definition,  however,  though 
a  strictly  scientific  one,  seems  rather  too  broad  for  our  present 
needs,  for  by  it  the  soils,  water,  ice,  and  all  the  soft  as  well  as 
hard  materials,  are  classified  under  one  great  head.  Here  we  are 
only  to  consider  the  hard  rocks,  or  stones,  and  have  use  for  no 
others.  The  definition  should  be  kept  in  mind,  nevertheless,  for 
there  is  no  well  defined  line  between  a  sand  and  a  sandstone,  a 
clay  and  a  shale,  or  a  gravel  and  a  conglomerate. 

The  rocks  of  the  earth  are  divided  into  three  grand  classes, 
as  follows : 

/.     The  Igneous  or  Massive  Rocks. 

II.  The  Atmospheric,  or  Stratified  Rocks. 

III.  The  Metanwrphic,  or  Changed  Rocks. 

Let  it  be  understood  that  in  the  following  remarks  under 
classification,  the  chief  aim  has  been  to  present,  to  the  general 
reader  and  practical  worker,  a  mtere  outline  showing  how  rocks 
are  grouped.  It  is  utterly  impossible  to  describe  a  rock  without 
some  knowledge  of  minerals  on  the  part  of  the  reader,  hence  the 
following  brief  attempts  at  describing  each  rock  must  be  under- 
stood as  incomplete  and  greatly  limited  in  scope.  It  is  hoped 
the  descriptions  may  convey  some  ideas  to  the  practical  man  as  an 
aid  to  his  work,  as  well  as  act  as  references  for  the  rocks  to  be 
later  described. 


THE       IGNEOUS    ROCKS. 

The  Igneous  Rocks  are  those  made  by  the  agency  of  heat, 
that  is,  have  cooled  from  a  molten  condition.  They  are  also  call- 
ed the  massive  rocks,  because  of  their  structure,  which  is,  broadly 
speaking,  the  same  in  all  directions.  Also  the  term  eruptive 
is  applied  to  them,  because  of  their  origin  as  eruptive  molten 
masses.  These  rocks  occur  in  several  different  ways,  as  fol- 
lows: 

T.  Batholites,  or  those  immense  masses  of  igneous  rocks, 
as  granites,  which  form  the  axes  of  our  greatest  mountain 
ranges.  They  are  characterized  by  their  great  size,  their  evi- 
dent position  beneath  other  rocks,  and  the  fact  that  as  far  as  is 
known  they  descend  to  the  deep  interior  mass  of  the  earth. 

2.  Laccolites,   or   those   dome   shaped   rock   masses   which 
have  been   intruded  between   layers,   or   strata,   of   Other   rocks, 
lifting  them  up  like  immense  blisters.     They  differ  from  bath- 
olites  mainly  in  the   fact  that  they  rest  upon   other   rocks   and 
are  smaller  in  size. 

3.  Sheets  or  Sills,  or  those  occurrences  of  igneous   rocks 
which  lie  between  other  rocks  as  mere  sheets,  or  on  top  of  them 
They  differ  from  laccolites  in  that  they  are  everywhere  of  about 
the   same   thickness   and   have   caused   no   doming   of     superin- 
cumbent  rocks.     They  may  have  been   intruded  between   other 
rocks,  or  poured  out  upon  the   surface  as   lava  flows,   and   are 
usually  more  nearly  horizontal  than  vertical. 

4.  Dykes,  or  intrusive  masses  filling  fissures,  much  as  do 
mineral  veins.    These  dykes  usually  cut  across  other  rocks,  are  of 
great  length  on  the  surface  compared  with  their  width,  and  de- 
scending  to  unknown   depths.      They   are   usually   more   nearly 
vertical  than  horizontal, 

5.  Irregular   Masses,    such    as    volcanic    necks,    which    are 
merely  the  hardened  lava  in  the  throat  or  pipe  of  an   extinct 
volcano,  standing  up  as  a  more  or  less  conical  mass  after  the 
wearing  away  of  the  soft  cone.     Also,  we  have  very  irregular 
bodies  of  igneous  rocks  of  various  sizes  and  shapes  which  are 
intruded  into  overlying  rocks.     To  these,   for  lack  of  a  better 
name,  the  term  "stock"   is  applied.     As   a  grand   division,   the 
igneous  rocks  are  those  from  which  all  others  are  derived. 

CLASSIFICATION.. 
To  handle  this  subject  of  rock  classification  from  a  popular 


standpoint  is  a  delicate  task.  The  principles  underlying  it  can 
only  be  partly  stated,  for  obvious  reasons.  A  knowldge  of  min- 
eralogy cannot  be  expected,  and  all  that  will  be  done  in  what 
follows  is  to  attempt  to  render  intelligible  in  the  simplest  pos- 
sible manner,  the  main  features  of  the  subject.  A  working 
knowledge  of  the  simpler  minerals,  as  quartz,  feldspar  and 
mica,  will  be  assumed. 

The  igneous  rocks  are  classified  along  two  lines.  First, 
chemically,  they  range  from  acid  to  basic,  with  all  grad- 
ations between.  This  variation  results  in  the  formation  of  dif- 
ferent minerals,  so  that  the  chemical  rock  types  have  different 
appearances  Secondly,  these  rocks  are  classified  on  a  basis  of 
what  is  called  texture.  Those  which  have  cooled  at  great 
depths  from  a  molten  condition  have  done  so  slowly,  with  a 
result  that  they  are  thoroughly  crystallized,  often  coarsely  so. 
On  the  other  hand,  those  which  have  cooled  on  the  surface  and 
hence  quickly,  are  glassy,  at  times  being  a  simple  glass.  The 
thoroughly  crystalline,  deep  seated  rocks  are  called  plutonic, 
the  glassy,  surface  ones  are  called  volcanic.  Those  which  have 
cooled  and  solidified  a  short  way  below  the  surface  are  often 
spoken  of  as  dyke,  trap,  or  intermediate  rocks.  In  accordance 
with  these  two  lines  of  difference,  then  all  rocks  which  have 
solidified  from  a  molten  condition  are  classified.  It  will  be  not- 
iced that  there  are,  unfortunately,  two  kinds  of  intermediate 
rocks:  those  chemically  intermediate  and  those  occupying  a 
middle  position  on  the  basis  of  crystalline  texture.  However, 
when  an  intermediate  rock  is  mentioned,  one  of  the  latter 
kind  will  usually  be  meant,  or  a  dyke  rock.  The  meaning  of  the 
various  textures  may  be  looked  at  in  this  way.  A  granite,  for 
instance,  is  the  type  of  an  acid  plutonic  rock.  MJelted  and 
cooled  rapidly  it  would  form  a  glassy  volcanic  rock,  and,  of 
course,  called  a  rhyolite.  Melted  and  cooled  more  slowly,  yet 
not  so  slowly  as  a  deep  seated  rock  looses  its  heat,  an  inter- 
mediate acid  type,  with  some  crystals  showing,  would  result. 
This  rock  would  be  called  a  quartz-porphyry.  A  more  basic 
plutonic  rock,  as  a  diorite,  when  similarly  treated  would  yield 
a  volcanic  adesite  and  a  dyke  phase  porphyrite.  These  facts 
are  embodied  in  the  following  table,  in  which  only  the  few 
main  types  are  mentioned.  The  many  varieties  and  sub-types 
made  by  the  petrographer  are  not  necessary  in  such  a  report 
as  this. 


TABLE    OF     CLASSIFICATION. 


TEXTU  R  E 

COMPOSI  T  IOIN 

PLUTONIC 

INTERMEDIATE 

VOLCANIC 

Acid 

Granite 

Quartz-  Porphyry 

Rhyolite 

Syenite 

Porphyry 

Trachyte 

Intermediate 

Diorite 

Porphyrite 

Andesite 

Basic 

Gabbro 

Diabase 

Basalt 

Ultrabasic 

Peridotite 

l_l  M  BU 

RC3  ITE 

A  peculiar  fact  to  be  noted  about  these  rocks  is  this :  Of 
the  plutonic  rocks  the  acid  ones,  the  granites,  are  most  com- 
mon throughout  the  earth,  while  of  the  volcanic  rocks  the 
basic,  the  basalts,  are  best  developed.  Another  fact  is  to  be 
noted  regarding  the  different  names.  For  reasons  not  neces- 
sary to  state  here  the  names  of  the  intermediate  rocks,  quartz- 
porphyry,  porphyry  and  porphyrite,  are  being  dropped,  and  the 
volcanic  terms  used  to  cover  them.  For  example,  andesites  and 
porphyrites  are  called  merely  andesites. 

THE  INDIVIDUAL  ROCKS 

PLUTONIC. 

All  wholly  crystalline,  often  coarsely  so. 

1.  Granite:     The   granite    family   consists   of   acid    rocks, 
wholly  crystalline  with  a  coarse  to  medium  fine  grain,  and  of  a 
grayish  or  reddish  color.     Free  quartz,  in  colorless  crystals,  at 
times   tinged   bluish    or    reddish,    is    always    present.      Also     a 
white  or  reddish   feldspar,   usually  clouded  with  other  whitish 
substances,  and  some  dark  mineral,  as  brown  mica,  are  to  be 
seen.     In  some  rarer  granites  only  a  white  mica,     besides  the 
quartz  and  feldspar,  is  present.     The  granites  are     the     most 
easily  determined  of  all  the  igneous  rocks,  and  can  be  confused 
only  with  one  other  kind.     The  feldspar  of  a  true  granite  con- 
tains potash,  and  is  comparatively  acid.     A  rock  very  similar  to 
a  granite,  a  diorite  with  free  quartz,  differs  only  in  the  nature 
of  the  feldspar,  which  contains,  in  place  of  potash,     soda  and 
lime,  making  it  more  basic.     To  the  eye  of     any  one  but     a 
trained   observer,    the   two   rocks    appear   precisely   the      same, 

showing  colorless  quartz,  white  feldspar  and  some  dark  mi-n- 
eral.  This  diorite  with  quartz  is  called  a  granite-diorite,  grano- 
diorite,  or  quartz-diorite. 

2.  Syenite.     The  syenite  family  may  be  briefly  character- 


ized  as  granites  without  quartz.  They  are  comparatively  rare 
rocks,  especially  in  the  western  part  of  the  United  States.  In 
color  they  vary  about  as  do  the  granites,  from  shades  of  gray 
to  pinkish  or  reddish  tints.  The  minerals  are  simply  feldspar 
and  some  dark  colored  ones,  as  mica  or  hornblende. 

3.  Diorite.     Of    this    family    the    quartz    bearing    variety, 
grano-diorite,    has    already    been    mentioned.      The    other    vari- 
eties are  without  quartz  and  more  basic     than     syenites,     and 
have  about  the  same  grain  as  the  granites  and  syenites,  though 
averaging  a  little  finer.     The  fresh  rocks     are     gray  in     color 
typically,  but  darker  than  the  above  mentioned  types,  and  show 
a  white  feldspar  with  some  dark  mineral,  usually  hornblende. 

4.  Gabbro.     The  gabbro   family  is  the  most  basic  of  the 
normal   plutonic   rocks,    which   are   of   complex   nature.      These 
rocks  are  often  coarser  in   grain   than   any  yet   mentioned,   the 
individual  crystals  at  times  being  an  inch  or  so  in  diameter.     In 
general  their  color  is   grayish,   often   with   a   dark   olive   green 
tinge.     Other  colors  are  black,  brown,  green  and  in  some  vari- 
eties white.     The  minerals  present  are  a  white  feldspar,  often 
with  a  greenish  stain,  and  some  dark  mineral  which  may  be  dark 
green,  brown  or  black.      Some  types  are  wholly   feldspar,   and 
white  in  color.     The  gabbros  are  rare  rocks,  particularly  in  this 
western   region. 

5.  Peridotites.     These  rocks  are  a  peculiar   family     com- 
posed  entirely   of   dark   minerals.      The    feldspars   are   typically 
absent,  hence  the  rocks  are  called  ultra-basic,  for  the  dark  min- 
erals are  usually  black,  with  sometimes  a  tinge  of  green.  They 
alter   as    a    rule   to   the    common    mineral    and    rock    known   as 
serpentine. 

•  INTSRMEDIATJE;   ROCKS. 

These  rocks,  with  the  exception  of  the  diabases,  show  what 
is  called  porphyritic  texture.  As  far  as  appearances  are  con- 
cerned, this  texture  causes  the  rocks  to  show  well  developed 
crystals  of  some  mineral  set  in  a  paste  of  fine  grained  material 
which  usually  cannot  be  resolved  into  its  component  parts  by 
the  unaided  eye.  This  fine  grained  paste  is  called  the  ground 
mass ;  the  well  formed  crystals  set  therein  are  termed  pheno- 
crysts.  To  the  naked  eye  the  different  kinds  of  these  intermedi- 
ate rocks  are  distinguished  by  the  occurrnce  of  certain  miner- 
als in  well  developed  crystals  and  also  by  the  color  and  general 
appearance  of  the  ground  mass. 


They  are  as  follows : 

1.  Quartz-porphyry.     In   this    rock   are    seen    crystals      of 
clear  colorless  quartz,  with  sometimes  feldspar  and  mica,  all  set 
in  a  ground  mass  of  various  shades,  from  almost  black,  but  sub- 
transparent,   through   shades   of   red,   pink   and   grayish.      Tlhis 
ground  mass  varies  in  grain,  from  that     which     looks  like     an 
exceedingly   fine   grained   granite   to    apparently   almost    glassy. 
However,   as   with  the  granites,   free   quartz   is     characterictic. 
Where  the   ground   mass   is   noticibly   granite-like   though   very 
fine  in  grain,  the  rock  is  called  a  granite  porphyry. 

2.  Porphyry.     Often   this   rock   is   called     an      orthoclase 
porphyry   or   syenite   porphyry,    depending   upon   coarseness   of 
grain.     The  relations  between  this  rock  and  syenite  is  precisely 
that  existing  between  quartz  porphpry  and  granite.     Also  por- 
phyry and  quartz  porphyry  are  connected  in  the  same  way  that 
syenite  and  granite  are.     Free  quartz  is  absent,  and  the  minerals 
appearing  as  phenocrysts  are  feldspar,  typically  the  potash  var- 
iety, orthoclase,  with  often  mica  or     hornblende.     When     the 
ground  mass  appears   fine  crystalline  to   the  unaided   eye     the 
rcok  may  be  called  a  syenite  porphyry.     As  a  rule  the     rock 
looks  much  the  same  as  quartz  porphyry,  differing  in  that  free 
quartz  is  absent  and  replaced  by  white  or  glassy  feldspar. 

3.  Porphyrite.     These  rocks  are  the  chemical  equals  of  the 
diorites,  but  having  cooled  near  the  surface,  lack  their  crystalline 
texture.     They  are  usually  much  darker  rocks  than  the  preced- 
ing,  showing  well   developed  crystals — phenocrysts — of  typical- 
ly a  dark  mineral,  but  sometimes  a  white  feldspar,  in  a  dark 
gray,   dark  green,  or  even  black,   ground  mass.     As   with   the 
first  two  types  of   intermediate   rocks,   when   the   ground   mass 
appears   finely   crystalline   we  may   have   a      diorite     porphyry. 
These  rocks  often  assume  a  reddish  hue  when  weathered. 

4.  Diabases.     These  rocks  are  the  equivalent  of  the  gab- 
bros,    occuring   typically    as    dykes    and    laccolites.      They    con- 
stitute the  greatest  body  of  dyke  forming  rocks  known.   They 
are   seldom    porphyritic,    differing   from   the   preceding   but   are 
wholly  crystalline,   appearing  on   casual   observation     like     fine 
grained  diorites.     There  are,  however,  some  differences  of  note. 
As  with  the  diorites  they  are  composed  of  a  light  mineral  and 
a  dark  one,  but  the  dark  one  usually  has  a  dark  green  tinge  and 
a  greasy  luster  seldom  present  in  the     black     mineral     of     the 
diorites.    Also,  the  white  feldspar  in  the  true  diabases  is  seen  to 


be  in  well  formed  crystals  with  the  dark  mineral  crystallized 
around  and  between.  The  reverse  is-  true  with  the  other  wholly 
crystalline  rocks ;  the  black  mineral  shpws  the  best  crystal  form, 
with  the  white  feldspar  in  the  spaces  between. 

VOLCANIC    ROCKS. 

These  rocks  constitute  the  lavas,  or  surface  flows  of  molten 
rock.  In  texture  they  range  from  porphyritic  to  glassy;  chem- 
ically they  cover  the  same  range  as  the  plutonic  rocks,  from  acid 
to  basic.  The  common  term  "obsidian'  means  a  volcanic  glass 
of  any  chemical  constitution  whatever.  Being  cooled  lava 
flows  they  often  show  what  are  called  flow  or  fluxion  lines. 
Their  varieties  are  below,  and  it  is  to  be  remembered  that  these 
names  are  now  used  to  cover  both  volcanic  and  intermediate 
types  of  rocks. 

i.  Rhyolite.  These  rocks  are  the  most  acid  of  the  lavas, 
corresponding  chemically  to  the  granites.  In  color  they  are 
usually  various  shades  of  white,  gray,  blue,  pink  or  green,  but 
are  always  of  light  tints  except  the  obsidians,  which  may  ap- 
pear dark.  When  porphyritic,  they  look  like  quartz-porphyries, 
into  which  they  shade  by  insensible  gradations,  always  showing 
free  quartz.  When  no  crystals  of  any  kind  are  to  be  seen,  yet 
if  the  rock  is  not  all  glass,  their  typical  white  or  whitish  color 
serves  to  distinguish  them.  The  old  term  felsite  is  often  given 
to  these  white  varieties  which  are  too  fine  grained  to  show  any 
well  formed  crystals. 

2.  Trachyte.  The  trachytes  are  much  like  the  rhyolites 
in  appearance,  but  differ  in  showing  no  free  quartz.  The  only 
minerals  showing  are  typically  white  or  glassy  feldspar  with 
sometimes  a  small  amount  of  the  darker  varieties.  They  have 
usually  a  characterictic  rough  feel,  hence  the  name  trachyte, 
which  means  rough.  Specifically,  their  color  is  often  white, 
varying  to  shades  of  pinkish  white  or  green.  The  whiteness  is 
more  pronounced  than  in  the  rhyolites  because  of  the  absence  of 
glassy  quartz.  The  trachyte  obsidians,  like  the  rhyolitic  ones, 
are  darker,  often  black  in  large  fragments.  The  family  as  a 
whole  is  a  rare  one. 

Andesite.  This  family  of  rocks  is  much  darker  than 
the  two  volcanic  groups  already  mentioned.  The  color  ranges 
from  a  fairly  light  gray  to  a  black,  a  dark  gray  being  an  average 
hue.  The  well  formed  crystals — the  phenocrysts — show 
both  light  and  dark  in  color.  Some  andesites  show  black 


crystals  in  a  light  gray  ground  mas,s,  while  others  show  white 
feldspars  in  a  dark  gray  or  black  ground  mass.  In  some  vari- 
eties the  feldspars  are  glassy,  resembling  quartz  on  cursory  in- 
spection. Quartz  does  occur  in  one  variety,  known  as  dacite 
This  rock  bears  the  same  relation  to  an  andesite  that  a  quartz- 
diorite  does  to  a  diorite.  At  time  an  andesite  shows  no  crystals 
to  the  unaided  eye,  when  its  color  is  nearly  black,  much  like  a 
basalt.  A  noteworthy  fact  is  that  these  rocks  tend  to  weather  a 
dark  red  color,  due  to  the  iron  oxide  formed  by  atmospheric  agen- 
cies. 

4.  Basalt.     These  common  volcanic  rocks  are  prevailingly 
black  or  nearly  so.   They   show   discernable  crystals   less   offten 
than  the  above  types,  and  are  usually  finer  grained  and  more 
homogeneous  in  appearance.     However,  in  some  common  var- 
ieties small  grains  of  a  light  greenish  mineral  appear  on  close 
inspection — the  mineral  olivene — and  again,  at  times  crystals  of 
black  color  are  apparent  in  the  dark  ground  mass.     A  feature  of 
these  rocks  and  of  the  andesites  as-  well,  is  the  weathering     or 
spliting  into  so-called  "basaltic  columns.'     The  rock  mass  parts 
01  cleaves  into  long  prisms,  roughly  hexagonical  in  cross  section, 
forming  a  cluster  of  natural  columns. 

5.  Limbiirgite.     This  rare  and  unimportant  family  of  vol- 
canic and  intermediate  rocks  is  mentioned  merely  to  complete 
the  account  of  the  massive  igneous  rocks.     This  family  is  com- 
posed entirely  of  dark  minerals  set  in  a  paste  of  the  same  or  of 
glass  with  identical  chemical  composition.     The  color  therefore 
is  black  or  greenish  black  when  fresh,  weathering  to  a  dark  red. 

THE    TUFFS    AND    AGGUDM £RAT£S. 

Thus  far  have  been  listed  only  the  massive  igneous  rocks ; 
there  is  a  minor  group  of  rocks  formed  by  fire  agencies,  of 
much  less  geological  importance,  but  of  considerable  value  as 
building  material.  This  group  is  constituted  by  the  fragmental 
igneous  rocks,  or  tuffs  and  agglomerates. 

i.  Tuffs.  These  rocks  are  volcanic  ashes  and  cinders 
more  or  less  consolidated  into  firm  stone.  They  are  composed 
of  finely  divided  glassy  substances,  rock  fragments  of  the  vari- 
ous igneous  rocks,  and  often  with  mineral  grains  and  large 
pieces  of  stone.  They  are  named  in  accordance  with  the  chem- 
ical family  to  which  they  belong.  Thus,  there  are  (i)  rhyolite 
tuffs;  (2)  trachyte  tuffs;  (3)  andesite  tuffs,  and  (4)  basalt 
tuffs.  The  rhyolite  tuffs  are  most  common. 


2.  Breccia.     This  variety  of  fragmental  rock  is  composed 
of  pieces  angular  in  shape  and  varied  in  size,  usually  of  only  one 
kind  of  rock.     They  differ  from  tuffs  in  that  they  are  not  ashes, 
but  made  up  of  rock  fragments  of  some  size,  and  have  origin- 
ated either  by  the  explosive  action  of  a  volcano  or  the  crushing 
effect  of  pressure  exerted  in  the  earth's  crust.     The  fragments 
are  usually  cemented  by  a  paste  of  the  same  material,  finer  in 
grain. 

3.  Agglomerate.     This  rock  is  most  simply  described  as  a 
mixture  of  various  kinds  of  volcanic  rocks  in  the  form  of  semi- 
angular  or   rounded  boulders,    small   pieces   and     even     ashes. 
Many  agglomerates  are  hardened  volcanic  mud  containing  stones 
like  plums  in  a  pudding.     The  term  is  agglomerate,  to  distin- 
guish it  from  conglomerate,  which   latter  term  is     applied     to 
consolidated   gravels    deposited   by    water.      Both    names    mean, 
however,  a  mixture  of  materials. 

THE     ATMOSPHERIC     ROCKS. 

This  grand  division  of  the  rocks  embraces  those  which  owe 
their  formation,  directly  or  indirectly,  to  the  decomposing  action 
of  atmospheric  forces  on  previously  existing  rocks.  Their 
structure  is  that  called  stratified,  meaning  in  beds  or  layers.  The 
whole  division  is  often  called  the  stratified  rocks.  But  as  all  the 
varieties  are  not  truly  stratified,  the  term  is  not  all  embracing. 
In  general  there  are  two  primary  divisions  of  these  rocks,  of 
very  unequal  importance.  They  are  as  follows : 

/.     Holian  or  ^vind  formed  rocks. 
II.     Aqueous  or  water  formed  rocks. 

1.  Holian  rocks.     These   rocks   are  of  no  importance     in 
the  present  connection,  and  will  be  dismissed  with  a  few  words. 
They  consist  mainly  of  those  materials  piled  up  by  the     wind, 
such  as  the  sand  dunes  of  our  coasts.     Their  recent  deposition 
and  geological  youth  prevent  any  great  amount  of  consolidation, 
hence  the  group  needs  no  further  mention. 

2.  Aqueous  rocks.     This   group   is   often   called   the   sedi- 
mentary, because  they  are  largely  composed  of   sediments   de- 
posited by  water  action.  The  name  is  misleading,  for  they  are 
not  all  sedimentary  in  origin.     It  can  be  stated,  however,  that 
they  have  been  deposited  in  or  by  water.     The  materials  com- 
posing them  are  (i)  the  -residue  from  the  waste  of  other  rocks 
and  derived  directly  from  them;  and   (2)   that  material  derived 


from  other  rocks  by  their  decomposition,  held  in  solution  in 
water,  and  deposited  either  by  the  action  of  living  organisms  or 
by  chemical  precipitation.  Therefore  under  this  head  come 
two  divisions: 

a.  Sedimentary  Rocks. 

b.  Organic  and  Chemical  Rocks. 

Under  the  action  of  the  atmosphere  a  rock  breaks  down  in- 
to soft  incoherent  material  by  the  leaching  out  and  removal  of  its 
soluble  parts,  leaving  an  insoluble  residue.  Thus  a  granite  dis- 
integrates into  a  sandy  soil,  mostly  quartz  and  feldspar, 
moistened  with  alkaline  water.  Ultimately  nothing  is  left  but 
quartz  and  clay,  stained  with  iron  oxide  and  containing  water 
alkaline  with  potash,  soda  and  lime.  In  general  it  may  be  stated 
that  quartz  and  clay  are  the  two  least  soluble  minerals  com- 
monly encountered,  and  hence,  singly  or  together,  mark  the  end 
of  the  decomposition  of  any  rock.  It  is  to  be  noted  that  from  all 
rocks  except  the  most  acid  lime  is  washed  out  as  well  as  potash 
and  soda,  and  the  more  basic  the  rock  usually  the  more  lime. 
The  alkalies  play  no  particular  part  in  rock  building  but  the  lime 
does.  Hence  in  this  brief  and  popular  exposition  it  may  be  con- 
sidered that  a  decomposed  rock  will  yield  quartz  sand,  clay  and 
a  solution  of  lime.  The  metallic  oxides,  such  as  iron  and  man- 
ganese, reman  as  coloring  materials  merely,  and  are  of  no  es- 
sential importance.  However,  as  few  rocks  break  down  into  their 
ultimate  products  before  being  consodidated  into  new  rocks,  we 
may  expect  to  find,  and  do  find,  nearly  all  aqueous  rocks  to  be 
neither  pure  quartz,  pure  clay,  nor  pure  lime.  Keeping  these 
few  facts  and  causes  in  mind,  the  principle  varieties  will  illustrate 
their  results. 

SEDIMENTARY     ROCKS. 

1.  Conglomerates.     These  rocks  are  consolidated     gravels, 
resulting  from  the  wear  and  tear  of  waves  and  currents  upon 
preexisting   rocks.      The   material    composing   them   consists   of 
rounded   fragments   of  various   sizes,   often   cemented  by     finer 
material  of  like  nature.     These  pebbles  or  boulders,  as  the  case 
may  be,  are  often  of  various  kinds  of  rocks,  while  again  they  may 
be  all  of  one  sort. 

2.  Sandstones.     The  name  of  these  rocks  explains  their 
nature ;  a  stone  built  up  of  grains  of  sand.     The  ideal  sandstone 
is  composed  of  grains  of  pure  quartz,  representing  the  last  stage 


of  decay  of  preexisting  rocks.  But  as  most  sand  is  not  pure 
quartz,  neither  is  most  sandstone  of  pi1  re  quartz  grains.  As  a  re- 
sult, these  rocks  have  a  variety  of  colors,  depending  apon  the 
materials  present.  The  most  common  rhirurals  are  quartz,  feld- 
spar, mica  f  'kes,  garnet  and  many  other  dark  kinds.  There  is 
also  another  important  quality  of  sandstones.  Such  rocks  are 
composed  of  a  mass  of  grains  of  san^,  >il  in  and  cc.-'Vi:tec!  bv 
some  other  substance.  The  three  important  cementing  mater- 
ials are  (i)  silica  or  quartz;  (2)  lime,  and  (3)  iron  ozide.  Com- 
binations of  these  may  occur.  The  first  will  give  a  more  glassy 
appearance  to  the  rock  and  the  color  will  be  nearest  to  that  of 
the  original  sand  grains.  The  second  will  give  the  rock  a  white 
color  as  a  rule ;  the  third  will  give  the  stone  that  red  color  so  de- 
sired for  architectural  purposes. 

3.  Clay  Rocks.  The  one  rock  name  necessary  to  name 
under  this  head  is  shale.  A  clay  or  mud,  when  hardened  by 
natural  processes,  becomes  a  shale.  A  pure  clay  makes  a  pure 
shale;  a  sandy  clay  a  sandy  shale,  and  so  on,  with  all  gradations 
into  the  sandstone.  These  rocks  are  of  no  value  whtever  for  the 
purposes  of  this  report,  but  the  clay  rocks  mentioned  under  the 
last  grand  division  of  the  metamiorphic  rocks,  the  well  known 
slates,  are  very  important. 

ORGANIC    AND    CHEMICAL    ROCKS. 

There  are  only  two  varieties  of  these  rocks  of  any  parti- 
cular value  in  this  discussion.  They  are  these: 

/.     Siliceous  Rocks. 
II.     Lime  Rocks. 

Both  owe  their  origin  to  the  fact  that  certain  minute  animals 
secrete  either  lime  or  silica  from  the  water,  and  on  dying  their 
remains  accumulate  in  certain  places  to  form  rocks.  Also  chemi- 
cal reactions  play  a  part  in  accumulating  both  kinds  of  sub- 
stances. The  first,  or  siliceous  rocks,  are  formed  largely  by  the 
growth  and  depth  of  certain  low  forms  of  life,  as  sponges ;  the 
second  are  due  in  large  part  to  the  well  known  coral  polyp. 

I.  Siliceous  rocks  or  cherts.  These  rocks  are  very  fine 
grained,  sometimes  almost  glassy  in  appearance,  and  of  various 
colors  from  white  to  red,  green  and  black.  They  are  well  known 
under  the  name  flint  or  chert.  The  fact  that  they  are  seldom 
pure  silica  results  in  their  various  shades  of  color.  They  are  of 


no  use  as  building  stones,  but  some  have  achieved  success  as 
road  metal. 

2.  Lime  rocks  or  limestones.  Under  this  head  come  the 
limestones,  so  well  known  to  everyone.  In  color  they  vary  from  a 
pure  white  through  the  grays  to  a  dead  black,  the  black  being  due 
to  carbonaceous  material.  The  texture  varies  from  a  medium 
coarse  grain  to  very  fine  or  compact,  that  is,  showing  no  crystal 
forms  to  the  naked  eye.  The  crystalline  varieties  are  least  com- 
mon, and  are  not  marbles,  which  are  metamorphic  rocks.  Tlhe 
crystals  of  the  limestone  are  due  to  simple  solution  and  redeposi- 
tion,  while  the  marbles  owe  their  crystalline  texture  to  other 
causes.  A  drop  of  a  weak  acid  will  always  serve  to  identify  the 
lime  rock,  as  a  bubbling  of  gas  is  caused. 

METAMORPHIC     ROCKS. 

In  this  division  is  treated  those  rocks  which  have  been 
changed  from  their  original  condition  by  heat  and  pressure  into 
new  forms.  They  are  derived  from  both  the  igneous  and  at- 
mospheric rocks.  Geologically  they  constitute  an  extremely 
important  and  interesting  class;  economically  they  are  of  little 
value.  A  few  statements  will  serve  to  distinguish  the  main 
types.  They  will  be  taken  up  in  the  following  order : 

/.     Gneisses  and  Schists. 

II.  Slates  and  Quartzites. 

III.  Marbles  and  rocks  altered  chemicallly. 

GNEISSES    AND    SCHISTS. 

The  gneisses  are  usually  rather  coarsely  crystalline  rocks 
which  show  a  laminated  or  banded  structure  due  to  a  flowage 
under  pressure.  In  mineral  content  they  correspond  in  most 
cases  with  the  plutonic  rocks,  differing  from  them  in  the  evident 
structure.  A  few  varieties  are  derived  from  the  atmospheric 
rocks,  as  conglomerates  and  sandstones.  The  banded  structure 
i?  made  evident  by  the  arrangement  of  minerals  in  more  or  less 
parallel  planes.  The  colors  vary  precisely  as  do  the  colors  in  the 
rocks  from  which  the  gneisses  have  been  derived.  The  different 
varieties  are  named  in  a  general  way  from  the  rock  from  which 
the  gneiss  has  originated  or  resembles  most  closely.  For  in- 
stance, there  are  granetic  gneisses,  syenitic  gneisses,  conglom- 
erate gneisses  an  so  on. 

The  schists*are  similar  to  the  gneisses  in  that  they  are  banded 


or  laminated,  but  differ  in  that  these  laminations  are  much  finer, 
giving  the  rocks  the  power  of  splitting  along  fairly  parallel 
planes.  With  an  elimination  of  fine  distinctions,  then  the 
schists  are  finely  laminated  or  foliated  rocks  rather  fine  in  grain, 
with  mineral  content  roughly  parallel  to  that  of  the  gneisses  and 
hence  to  the  plutonic  rocks.  Their  most  obvious  difference  from 
the  gneisses,  into  which  they  grade,  is  in  their  finer  banding.  In 
color  they  range  from  white,  in  the  quartz  schists  to  black  in  the 
basic  varieties.  They  are  named  from  the  dominent  mineral 
showing,  which  minral  is  usually  arranged  in  more  or  less  par- 
allel layers,  and  causing  the  rock  to  split  readily  along  these 
planes.  The  schists  are  derived  both  from  the  igneous  and  the 
atmospheric  rocks.  The  two  chief  varieties  are  the  mica-schists, 
showing  bands  of  brown,  black  or  white  mica,  and  the  horn- 
blende-schists, otherwise  called  amphibolite-schists  or  greenstones. 
None  of  these  are  of  particular  value  in  this  paper. 

SLATES     AND     QUARTZITES. 

When  an  ordinary  clay  rock,  or  shale,  is  squeezed  under 
pressure,  as  often  happens  in  mountain  regions,  it  is  made  to 
flow  at  right  angles  to  this  pressure.  Certain  molecular  changes 
set  up  in  the  mass  cause  it  to  assume  a  structure  which  results 
in  its  splitting  easily  along  parallel  planes  into  thin  slabs.  This 
structure  is  called  slaty  structure,  the  cleavage  is  slaty  cleavage, 
and  the  rocks  themselves  are  slates.  They  are  formed  in  similar 
manner  from  igneous  rocks  also.  The  typical  slate  is  not  crystal- 
line ;  some  varieties  show  incipient  crystallization  and  shade  by 
insensible  gradations  into  the  schists.  Their  economic  import- 
ance is  too  well  known  to  need  discussion. 

The  quartzites  are  rocks  composed  chiefly  of  silica,  or 
quartz.  They  have  usually  been  derived  from  siliceous  rocks, 
as  quartzose  sandstones,  by  the  addition  of  more  silica,  binding 
the  whole  into  a  hard,  compact  mass.  Geologically  no,  old  sand- 
stones frequently  are  converted  into  quartzites  by  long  continued 
action  of  heat  and  moisture.  Quartz  schists  and  quartzite 
gneisses,  and,  in  fact,  all  metamOrphic  rocks  mainly  silica,  come 
under  this  head. 

MARBLES    AND    CHEMICALLY    ALTERED    ROCKS. 

The  marbles,  properly  speaking,  are  those  rocks  which  have 
been  derived  by  the  crystallization  of  the  limestone  by  the  ac- 
tion of  heat  and  moisture  with  perhaps  pressure.  They  are 
ofter  of  coarser  grain  than  the  crystalline  limestones.  The  pure 


varieties  are  white  in  color,  composed  entirely  of  lime,  or  lime 
and  magnesia.  When  made  from  impure  limestones  the  impur- 
ities crystallize  out  as  other  minerals,  of  varying  shades  from 
white  through  reds  and  greens  to  black.  The  purer  varieties  of 
marble,  which  are  of  value  for  ornamental  stones,  are  of  even 
grain,  the  crystals  showing  shining  faces.  The  test  with  acid 
always  serves  to  identify  these  rocks.  It  is  to  be  noted  that 
there  are  two  kinds  of  limestones ;  ( I )  those  composed  entirely  of 
lime,  and  (2)  those  composed  of  lime  and  magnesia.  The  sec- 
ond, or  lime-magnesia  rocks,  are  called  dolomites,  or  dolomitic 
limestones,  when  only  a  small  percentage  of  magnesia  is  present. 
In  appearance  there  is  usually  no  differense ;  the  dolomites  are 
less  acted  upon  by  a  cold  dilute  acid. 

The  serpentines  are  a  group  of  chemically  altered  rocks  of 
light  or  dark  green  to  greenish  black  color,  and  usually  of  very 
fine  grain.  Sometimes  well  formed  crystals  with  shiny  surfaces 
are  seen  set  in  the  finer  material.  These  rocks  have  resultd  from 
the  chemical  addition  of  water  to  the  peridotiles,  or  ultrabasic 
plutonic  rocks.  They  are  of  some  value  as  ornamental  stones. 

Steatite,  better  known  as  talc  and  soapstone,  is  also  a 
chemically  altered  rock,  similiar  to  serpentine.  In  color  the 
pure  varieties  are  greasy  white,  often  with  a  light  greenish  tinge. 
They  are  best  known  by  their  greasy  feel.  Other  types  of  these 
altered  rocks  exist,  but  none  of  importance  in  this  place.  Steatite 
is  often  used  for  furnace  foundations  and  other  places  where  a 
fire  proof  material  is  needed. 

This  subject  of  rock  classification  is  one  of  great  complex- 
ity and  difficulty,  particularly  in  regard  to  the  grand  division 
of  the  igneous.  Necessarily  the  matter  has  been  presented  as 
one  concerned  with  hard  and  fast  rock  varieties,  with  more  or  less 
fixed  differences.  This  is  not  so,  for  there  are  no  well  defined  lines 
separating  any  of  the  various  rock  types,  yet  after  all,  it  is  the 
types  which  are  of  particular  value  here,  and  not  the  finely  drawn 
conditions  and  conclusions  of  petrography. 


CHAPTER  III. 

QUALITIES    OF    BUILDING    STONES. 

This  chapter  is  divisable,  by  reason  of  its  nature,  into  three 
parts.  One  speaks  of  the  qualities  of  a  certain  stone,  with  its 
consequent  value  for  architectural  purposes.  These  qualities  are 
of  value,  first,  because  of  the  inherent  power  of  the  stone  to  re- 
sist those  changes  which  tend  to  impair  its  usefulness,  and 
second,  because  of  the  resultant  appearance  of  the  rock.  These 
characteristics  are  estimated  in  a  number  of  ways.  Hence,  the 
divisions  of  this  chapter  are  as  follows :  First,  an  account  of 
the  many  possible  changes  to  which  a  building  stone  may  be 
subjected;  second,  a  description  of  the  features  which  govern 
these  changes ;  and  third,  a  brief  notice  of  the  ways  in  which 
these  these  qualities  are  estimated.  The  treatment  of  all  this 
will  be  brief,  a  full  discussion  being  reserved  for  a  detailed  re- 
port to  be  issued  at  a  later  date. 

CHANGES    IN    ROCKS. 

These  will  be  discussed  under  the  following  outline: 
A — Physical  Changes,  due  to 

I.  Temperature  changes. 

II.  Mechanical  wear  and  tear. 

III.  Effect  of  pressure. 
B — Chemical  Changes,  due  to 

I.  Atmospheric  solution. 

II.  Decomposition  of  certain  minerals. 

PHYSICAL    CHANGES. 

I.  Temperature.  The  results  under  this  division  are  of 
two  sorts,  and  due  to  different  qualities  in  any  particular  stone 
The  first  are  those  results  produced  by  the  alternate  expansion 
and  contraction  of  a  rock,  and,  of  course,  of  its  component  min- 
erals, due  to  heat  and  cold.  This  process  is  the  most  important 
method  of  rock  disintegration  in  regions  of  little  moisture,  as  in 
our  typical  deserts  of  the  west.  During  the  day  the  stone  be- 
comes warm,  or  even  hot,  and  expands.  At  night  the  temper- 
ature lowers,  the  stone  contracts,  and  the  changes  being  usually 
rather  sudden  and  of  unequal  amounts  in  all  directions,  chips  of 
rock  fly  off.  The  Indians  use  this  principle  in  manufacturing 
arrowheads.  After  heating  a  suitable  fragment  in  a  fire,  by 


touching  any  desired  portion  with  a  drop  of  cold  water,  un- 
equal contraction  is  produced  and  a  small  piece  chips  off.  In 
regions  of  equable  temperature,  as  along  the  western  coasts,  lit- 
tle is  to  be  feared  from  such  action ;  in  Nevada,  where  the  daily 
changes  are  often  pronounced,  some  importance  is  to  be  attached. 
The  mineral  composition  and  texture  of  a  building  stone  largely 
determine  how  greatly  it  shall  be  so  acted  upon.  The  loose  tex- 
tured fragmental  rocks  suffer  least,  because  of  their  ability  to 
take  up  without  rupture  small  inequalities  of  motion  in  their 
mass.  The  massive  igneous  rocks  suffer  most  because  of  their 
internal  rigidity  and  the  fact  that  each  one  of  the  constituent 
minerals  expands  and  contracts  differently  from  the  others.  The 
volcanic  or  partly  glassy  igneous  rocks  are  probably  most  liable 
to  such  disintegration,  the  plutonic,  because  of  their  inter- 
locking grains,  are  less  so. 

The  second  result  from  temperature  changes  is  due  to  the 
freezing  of  included  water.  All  rocks  are  porous  to  a  greater  or 
less  extent,  the  crystalline  least  of  all  and  the  fragmental  most 
so.  Also  the  tendency  of  all  rocks  to  break  into  large  fragments 
or  masses,  often  rudely  regular  in  shape,  by  means  of  parallel 
cracks,  or  joint  planes,  as  they  are  called,  allows  water  to  act  in 
this  way.  The  massive  rocks  especially  are  subject  to  jointing* 
action,  which  may  be  either  on  a  large  scale  or  a  very  minute 
one.  In  some  instances  these  joints  become  apparent  only  on  the 
weathering  of  the  stone.  Water,  penetrating  the  free  spaces  and 
cracks  in  rocks  on  freezing  expands,  and  exerts  a  tremendous 
force  acting  to  disrupt  the  material. 

2.  Mechanical  wear  and  tear.  The  conditions  under 
which  a  stone  is  to  be  used  determines  very  largely  the  changes 
coming  under  this  head.  Stones  for  paving,  for  tiling,  for  floors, 
and  for  walks,  all  must  be  chosen  to  resist  the  constant  wear  of 
pressing  feet  and  vehicles.  Rocks  for  curbing,  subject  to  hard 
knocks  and  the  rubbing  of  wagon  tires,  must  be  had  resistant  to 
such  abrasion.  Such  stones  should  be  homogeneous  and  without 
flaws,  otherwise  disastrous  breakage  may  occur.  Two  less  im- 
portant considerations  in  this  connection  yet  of  too  great  value  to 
omit,  are  (i)  the  action  of  wind,  bearing  sand  and  other  parti- 
cles, on  the  rock  of  a  building;  and  (2)  the  erosive  and  wearing 
effects  of  water,  particularly  in  a  country  of  consdierable  rain- 
fall. The  hardness,  toughness  and  texture  of  a  building  material 
govern  its  strength  or  weakness,  of  which  more  will  be  stated 
further  on. 


3.  Effects  of  pressure.  The  most  important  consideration 
here  is,  obviously,  the  fact  that  a  stone  selected  for  purposes  of 
construction  must  be  sufficiently  strong  to  withstand  all  the  force 
applied  to  it.  For  buildings  not  of  large  size  the  average  stone 
has  strength  far  above  that  required ;  in  large  structures  some 
attention  must  be  paid  this  factor  of  utility.  The  effect  of  pres- 
sure or  strain  on  a  rock  is  that  of  crushing,  each  variety  of  build- 
ing material  having  its  own  crushing  strength,  as  it  is  called. 
These  figures,  expressed  in  pounds  per  square  inch  mean  the 
force  necessary  to  crush  a  cube  one  inch  on  an  edge.  Some 
average  figures  are  as  follows : 

Granite — 15,000  to  40,000  pounds  per  square  inch. 
Volcanics — 10,000  to  30,000  pounds  per  square  inch. 
Marble — 15,000  to  25,000  pounds  per  square  inch. 
Sandstone — 4,000  to  8,000  pounds  per  square  inch. 
Tuffs — 2,000  to  6,000  pounds  per  square  inch. 

Results  both  above  and  below  these  are  often  obtained,  the 
hardest  granite  and  rhyolite  showing  a  strength  of  about  50,000 
pounds  per  square  inch  of  surface,  while  other  varieties  will 
crush  at  a  pressure  of  10,000  or  12,000  pounds,  or  even  less.  In 
use,  a  factor  of  safety,  usually  of  from  six  to  ten,  is  employed. 
But  there  is  more  to  the  crushing  strength  of  stone,  however. 
An  important  relation  exists  between  the  strength  of  a  building 
material  and  its  structure.  A  limestone  or  sandstone,  for  in- 
stance, is  much  more  able  of  sustaining  a  given  load  when  laid 
parallel  to  its  bedding  plane.  It  is  a  well  known  tenet  of  the 
masonry  trade  that  a  stone  should  never  be  laid  on  edge,  par- 
ticularly one  of  the  sedimentary  or  laminated  rocks.  The  same 
holds  good  in  the  other  rocks,  even  seemingly  structureless  gran- 
ite, for  there  is  often  some  one  direction  in  which  such  a  rock 
will  cleave  or  break  most  easily.  This  plane  should  always  be 
laid  at  right  angles  to  the  direction  of  pressure.  Lastly,  there 
is  a  further  consideration  growing  out  of  all  these  facts.  All 
stones  are  brittle,  hence  must  be  handled  carefully  to  avoid  shat- 
tering. The  most  incipient  fractures,  of  microscopic  dimensions, 
will  in  time  ruin  even  the  hardest  rock.  Quarrying  should  be 
done  by  the  most  approved  methods,  so  that  this  danger  of 
ruining  future  buildings  shall  be  reduced  to  a  minimum. 


CHEMICAL  CHANGES 

i.  Atmospheric  Solution.  Under  this  head  comes  the  mere 
dissolving  out  and  carrying  away  of  certain  parts,  or  the  whole, 
of  a  rock.  The  chief  agent  of  atmospheric  action  is  carbon 
dioxide  or  carbonic  acid  gas,  which  in  time  decomposes  nearly 
every  rock  forming  mineral.  Marbles,  limestones  and  such  rocks 
dissolve  completely.  Other  rocks,  as  granite,  hctve  certain  ele- 
ments leached  out,  causing  a  crumbling  of  the  remainder.  The 
alkali  metals  enter  into  minerals  and  compounds  which  are  easily 
extracted  by  the  water.  The  decomposition  of  granite  into  sand 
composed  of  quartz,  feldspar  and  other  mineral  fragments  has 
been  mentioned  under  the  atmospheric  rocks.  The  densest  and 
least  porous  of  the  rocks  are  obviously  least  libable  to  this  action 
of  solution,  and  a  compact  marble,  if  not  broken  or  shattered 
in  any  way,  resists  for  a  long  time  the  attack  of  the  atmosphere. 
In  the  igneous  rocks  the  iron  bearing  minerals  are  easily  acted 
upon  and  partially  leached  out.  Hence  the  mineralogical  compo- 
sition of  a  stone  has  an  important  bearing  upon  its  commercial 
value. 

2.  Decomposition  of  certain  minerals.  Here  will  be  briefly 
outlined  some  noteworthy  results  produced  by  the  decomposition 
.of  certain  minerals.  The  oxygen  and  water  vapor  of  the  air, 
combining  with  the  sulphide  minerals,  such  as  ordinary  pyrite, 
produce  sulphuric  acid  and  iron  oxide.  This  strong  acid  rapidly 
attacks  the  minerals  with  which  it  comes  in  contact,  while  the 
iron  oxide  stains  the  rock  a  yellowish  or  reddish.  Pyrite  is  common 
in  all  rocks,  and  lessens  their  value  for  structural  purposes  in 
proportion  to  its  relative  abundance.  An  abundance  of  iron  in 
any  rock  will  cause  it  in  time  to  become  stained  a  dissagreeable 
yellow  color.  There  are  many  other  reactions  of  a  similar  nature, 
but  of  subordinate  importance  and  do  not  need  mentioning.  The 
ultimate  value  of  a  stone  is  greatly  influenced  by  these  consider- 
ations. 

II.  ROCK  CHARACTERISTICS 

i.  Color.  This  feature  of  a  stone  is  governed  by  the  col- 
ors and  relative  amounts  of  its  component  parts  and  minerals. 
For  instance,  .a  granite  is  gray  because  of  the  blending  of  the 
black  mica,  white  feldspar  and  colorless  quartz.  The  value  of  a 
stone  is  largely  governed  by  its  color,  irrespective  of  other  char- 
acteristics. Other  things  being  equal  a  red  sandstone  will  be  more 
sought  after  than  a  dull  gray  one;  a  red  granite  will  often  com- 


mand  a  higher  price  than  one  with  a  somber  hue.  The  variation 
in  tint  of  any  particular  rock  also  changes  its  commercial  value, 
as  uniformity  in  all  things  is  desired.  Many  stones,  otherwise 
first  class,  are  denied  a  place  in  the  market  because  of  such  a 
defect.  Besides  the  variation  in  color  of  a  stone  from  one  point 
to  another,  it  is  also  to  be  noted  that  on  drying  or  mere  exposure 
to  the  air,  some  change  in  the  tint  may  occur.  This  may  be  a 
deepening  of  color  due  to  partial  oxidization  or  surface  chem- 
ical change ;  again  it  may  be  a  bleaching  due  to  drying.  Often  a 
rock  with  an  abundance  of  iron  assumes  a  reddish  or  dark  red 
hue,  due  to  the  deposition  of  iron  oxide  throughout.  Many  of  the 
Nevada  andesites  now  used  in  construction  are  thus  altered.  The 
color  is  pleasing  to  the  eye,  but  the  stone  is  weakened  in  the  pro- 
cess. Sometimes  it  is  less  a  change  of  color  than  a  decrease  in 
the  luster  of  a  rock  surface.  This  effect  is  common  on  granites, 
whose  materials  become  either  slightly  altered  on  thier  exposed 
parts,  or  covered  by  a  film  of  dust. 

For  ornamental  work,  as  in  cornices  and  monuments,  the 
ability  of  a  stone  to  show  a  contrast  between  the  appearances  of 
its  polished  and  rough  hewed  surfaces  is  of  great  value.  The 
crystalline  rocks  possess  this  power  in  the  highest  degree,  because 
of  the  fine  polish  possible.  When  such  materials  are  carved  and 
their  exteriors  smoothed,  the  contrast  lies  in  the  fact  that  a  broken 
surface  reflects  more  white  light,  while  the  ponshed  surface, 
which  exhibits  the  colors  of  the  minerals,  absorb  more  of  the 
sun's  rays.  A  certain  granite,  valuable  as)  a  building  material 
and  monumental  stone,  polishes  a  very  dark  gray,  while  roughing 
to  a  light  or  whitish  gray  tint. 

The  selection  of  color  is  mainly  from  two  standpoints :  taste 
or  fashion,  and  utility.  In  regard  to  taste,  there  is  nothing  to 
state  from  the  view  point  of  this  paper  except  that,  other  things 
being  equal,  a  warm  tint  is  preferable  to  a  colder  one.  Concern- 
ing utility,  it  needs  to  be  emphasized  that  certain  colors  are  more 
suitable  for  particular  localities,  as,  for  instance,  a  gray  sandstone 
should  be  selected  for  a  building  in  a  manufacturing  center, 
where  smoke,  dust  and  grime  are  ever  present.  And  oil  the  other 
hand,  white  stones  should  be  used  only  where  least  exposed  to 
tarnish. 

2.  Hardness.  The  hardhess  of  a  stone  is  its  resistance  to 
abrasion,  shown  usually  by  resistance  to  rubbing.  Necessarily, 
the  most  important  characteristic  of  a  rock  underlying  this  is  its 
mineralogical  content,  a  rock  containing  an  abundance  of  thte 


harder  minerals,  as  quartz,  being  the  hardest,  and,  as  all  minerals 
vary  in  hardness,  their  relative  abundance,  state  of  aggregation, 
and  size  of  crystals,  govern  the  resistance  of  a  stone  to  abrasion. 
A  sandstone  composed  of  grains  of  hard  quartz  may  be  very  soft 
because  of  the  loose  hold  they  have  upon  one  another.  The  chief 
reason  for  the  greater  hardness  of  the  plutonic  rocks  is  because 
their  component  minerals  mutually  interlock  and  bind  the  whole 
firmly  together.  Also  in  the  metamorphic  quartzites,  the  little 
broken  pieces  of  quartz  have  grown  by  the  addition  of  more 
silica  until  a  similar  interlocking  texture  is  produced.  A  sand- 
stone-cemented by  lime  or  iron  oxide  is  softer  because  the  grains 
do  not  bind  one  another  together.  In  all  the  sedimentary  and 
laminated  rocks  variations  in  hardness  may  occur  in  the  different 
layers  or  laminae  caused  by  a  change  in  any  or  all  of  the  condi- 
tions of  the  minerals  mentioned  above.  As  a  result,  much  care 
must  be  exercised  in  their  use.  In  the  crystalline  and  more  brit- 
tle rocks  it  must  be  kept  in  mind  that  even  the  slightest  shatter- 
ing by  improper  handling  lowers  the  hardness  and  hence  the 
value. 

3.  Strength.  The  strength  of  a  stone  is  its  resistance  to  ap- 
plied pressure,  either  compressive  force  or  transverse  strain. 
This  quality  is  very  closely  allied  to  hardnesis  and  depends  in 
general  upon  the  same  internal  conditions :  mineral  content,  state 
of  aggregation,  and  size  of  grain.  As  has  been  pointed  out  under 
"effects  of  pressure,"  in  large  structures  the  power  of  a  stone  to 
sustain  a  load  is  of  great  moment,  while  in  small  buildings  and 
other  ordinary  uses,  it  matters  little.  It  is  not  an  unusual  sight 
to  see  in  large  stone  structures  that  the  material  near  the  base 
shows  undoubted  signs  of  crumbling,  due  to  an  overload.  Every 
edifice  erected  is  constantly  jarred,  and  this  small  in- 
appreciable motion  has  its  lasting  effect  upon  a  rock 
already  taxed  to  sustain  a  weight  too  near  the  limit  of  safety. 
More  facts  pertinent  to  this  matter  have  been  mentioned  under 
"effects  of  pressure." 

Another  characteristic  of  certain  building  stones  has  a  direct 
bearing  on  both  hardness  and  strength.  It  is  the  power  of  some 
rocks  to  harden,  or  temper,  on  exposure  to  the  air.  In  particular, 
some  of  the  tuffs  show  an  ability  to  temper  to  considerable  hard- 
ness, at  times  sufficient  to  turn  the  edge  of  an  ordinary  hammer. 
The  last  bit  of  interstitial  water  of  the  rock,  on  working  its  way 
out  to  the  surface,  deposits  whatever  it  holds  in  solution  in  the 
outer  parts  of  the  mass,  and  at  times  a  perceptable  crust  is  formed, 


which,  when  broken  through,  exposes  the  softer  stone  beneath. 
Hence  a  rock  once  laid  and  undergoing  this  process  of  tempering 
should  not  be  disturbed. 

4.  Structure.     Broadly  speaking  wre  have  massive  rocks, 
such  as  the  igneous ;  stratified  rocks,  as  the  sedimentary ;  schistose 
rocks,  and  so  on.    These  are,  properly  speaking,  rock  structures. 
There  are,  also,  other  structures  of  the  utmost  importance.  Joints, 
which   have   already  been   mentioned,   are   common.      Irregular 
cracks  and  openings  of  all  sizes,  down  to  miscroscopic  joints  pro- 
duced by  movement  and  pressure,  come  likewise  under  this  head. 
All  these  determine  very  largely  just  how  long  a  stone  will  last 
under  given  conditions.    The  massive  rocks,  those  whose  charac- 
teristics are  constant  in  all  directions,  are  best  fitted  for  long  life ; 
the  stratified  or  laminated  ones  are  liable  to  allow  rather  free  ac- 
cess of  water,  with  resultant  deleterious  effect,  especially  if  not 
laid  properly. 

5.  Texture.     The  texture  of  a  rock  enters  largely  into  the 
various    factors    which    govern    its    strength    and    resistance   to 
change.     The  different  textures,  or  internal  arrangements,  have 
been   stated  under  rock  classification,   so  that  but  little  in  the 
way  of  reiteration  is  needed  here.  A  knowledge  of  the  size,  ar- 
rangement, and  mutual  relations  of  the  minerals  or  parts  of  a 
rock  are  of  the  utmost  value  in  estimating  the  worth  of  such  ma- 
terial for  structural  purposes.    For  reasons  given,  a  porous  sand- 
stone is  weaker  than  a  more  compact  one  of  the  same  composi- 
tion, and  should  not  be  used  in  work  requiring  any  particular 
strength.     In  the  fragmental  rocks  the  value  of  the  cementing 
substance  is  all  important.    As  a  general  rule  it  may  be  stated  that 
the  hardest  rock  is  that  in  which  the  binding  material  is  of  the 
same  nature  as  the  mass.     The  texture  of  the  plutonic  rocks  is 
commonly  spoken  of  as  "granitic,"  because  of  the  similarity  with 
that  of  true  granite ;  an  interlocking  mass  of  crystals. 

6.  Mineral  Content.  Very  little  can  be  written  at  this  time 
about  the  various  rock  forming  minerals,  because  no  knowledge 
of  the  subject  is  assumed  on  the  part  of  the  reader.  To  enter  upon 
a  thorough  outline  of  such  a  matter  is  beyond  the  scope  of  the 
present  paper,  and  will  be  reserved  for  a  later  date.  Quartz,  feld- 
spar, mica,  and  hornblende  have  been  referred  to,  because  they 
not  only  are  commonly  known,  but  also  are  among  the  most  im- 
portant. The  importance  of  the  mineral  content  has  been  conclu- 
sively shown  already  in  the  several  connections,  so  that  no  new 
space  need  be  devoted  to  the  subject. 


III.  OBSERVATIONS  ON  ROCKS 

1.  Quarry.     From  the  quarry  one  learns  the  color  of  a  rock, 
or  its  colors,  as  the  case  may  be,  its  hardness,  structure,  weight, 
and  something  about  its  texture.  Also,  the  main  minerals,  m&y 
be  determined  with  the  resistance  they  offer,  severally  and  col- 
lectively, to  the  atmospheric  agents  of  dcomposition.     The  ability 
of  a  rock  to  temper  well,  the  colors  of  the  rough  and  tpolished 
surfaces,  with  much  about  the  larger  features,  can  be  ascertained. 
The  weathering  effects  often  show  important  things.     All  incip- 
ient joint  planes,  all  lines  of  weakness,  all  traces  of  lamination, 
which  are  not  noticed  in  the  fresh  stone,  are  brought  to  light  in 
the  slightly  altered  portions.     Changes  in  color  are  caused  in  like 
manner,  due  both  to  bleaching,  and  to  staining  by  the  decompo- 
sition of  particular  minerals.    Lastly,  the  quarry  shows  unmistak- 
ably the  average  character  of  the  rock  and  not  alone  its  best 
specimens,   and  the  amount  possible  to  expect   for   commercial 
purposes.     Quarrying  in  some  of  its  details,  is  much  like  mining 
The  owner  almost  invariably  selects  the  best  piece  of  rock  to  be 
found  to  exhibit — and  who  can  blame  him — with  the  result  that 
often  totally  erroneous  ideas  may  be  conceived  and  ultimate  in- 
jury done  to  a  good  business  proposition. 

2.  Buildings.     This  is  an  important  means  of  determining 
the  value  of  a  given  material.     It  is  not,  however,  as  some  think, 
the  best  or  only  means,     A  stone  which  has  proved  a  failure  in 
one  building  may  owe  its  poor  showing  not  to  inherent  weakness, 
but  to  a  number  of  various  causes,  of  wjiich  the  most  common 
are  the  improper  working  of  the  rock  preparatory  to  laying,  and 
the  lack  of  consideration  regarding  the  qualities  demanded  by  the 
structure.     The  permanence  of  color  and  temper,  the  power  to 
withstand  the  attacks  of  the  wind  and  dust,  the  effect  of  sustained 
load,  in  a  word  the  permanence  of  the  material,  may  be  largely 
ascertained  by  these  observations.     In  such  estimations  it  is  to 
be  borne  in  mind  that  many  things  must  be  regarded  as  influenc- 
ing deterioration.    For  instance,  some  buildings  are  more  exposed 
than  others  to  all  sorts  of  active  agients,  as  tine  acids  in  manu- 
facturing districts.    And  in  every  case  there  are  multitudinous  lit- 
tle details  which  every  fair  minded  observer  should  notice.     No 
stone  should  be  condemned  because  of  one  or  two  failures,  as  in 
this  way  a  blow  is  dealt  an  important  industry. 

3.  Chemical.     Since  the  decomposition  of  any  building  ma- 
terial is  strictly  a  chemical  process,  a  knowledge  of  its  chemical 
constituents,  and  hence  properties,  is  necessary  if  we  would  thor- 


oughly  understand  it's  fitness  for  use.  In  investigating  this  qual- 
ity of  a  stone  we  need  simply  to  apply  chemical  principles  to  thje 
determined  composition  in  order  to  throw  light  on  possible  alter- 
ation. For  a  simple  examiple,  a  sandstone  ninety-six  per  cent, 
silica  is  obviously  far  more  servicable  than  one  containing  fifteen 
per  cent,  of  lime.  A  type  analysis  will  be  found  under  granites 
in  chapter  IV. 

4.  Physical  Tests.  These  are  of  several  kinds,  all  of  funda- 
mental importance,  and  serve  to  fill  out  the  knowledge  gained  by 
the  methods  already  mentiond. 

a.  The  strength  of  a  stone  is  measured  directly  in  a  testing 
machine  by  applying  force  to  carefully  cut  blocks.     Commonly 
two  inch  cubes  are  crushed,  the  figures  obtained  being  corrected 
to  ultimate  crushing  strength  per  square  inch  of  surface.     The 
machines  used  are  those  employed  in  the  testing  of  strengths  of 
materials  in  engineering  laboratories.   The   Nevada   State  Uni- 
versity is  not  yet  equipped  with  such  apparatus,  which  is  one  of 
the  main  reasons   for  the  incompleteness  of  the  report.      Such 
a  machine,  with  a  limit  of  200,000  pounds  pressure  costs  in  the 
neighborhood  of  $10,000.     The  transverse  strength  is  tested  by 
using  a  suitable  prism  of  stone,  laid  crosswise  on  supports. 

b.  The  specific  gravity  of  a  stone  is  the  ratio  of  its  weight  to 
the  weight  of  an  equal  volume  of  water.     The  common  term 
''weight"  is  used  in  practice,  and  is  similar  but  not  the  same,  as 
' 'specific  gravity."     For  instance,  a  cubic  foot  of  water  weighs 
about  63  pounds,  and  its  specific  gravity  is,  of  course,  I   (one) 
The  specific  gravity  of  a  granite,  let  be  assumed,  is  2.65.  Hence 
its   weight  per  cubic   foot,   were   it   absolutely   solid,   would  be 
63x2.65,  or  about  225  pounds.    As  a  matter  of  fact,  the  porousity, 
or  air  space,  reduces  this  figure,  which  would  be  about  175  pounds 
weight.    To  obtain  this  figure,  a  simple  and  fairly  accurate  meth- 
od is  as  follows.  A  representative  piece  of  the  rock  to  be  tested 
is  obtained,  say  containing  about  four  cubic  inches.  This  is  thor- 
oughly cleaned  of  all  loose  particles,  dried  at  no  deg.  Centigrade, 
and  carefully  weighed  in  air.     It  is  then  suspended  by  a  hair  in 
boiling  distilled  water  for  at  least  an  hour,  and  after  cooling  to 
the  temperature  of  the  air  it  is  weighed  in  the  water.     The  dif- 
ference in  the  two  weights  gives  the  weight  of  an  equal  volume  of 
water,  which,  divided  into  the  dry  weight  of  the  stone,  gives  its 
specific  gravity.    The  boiling  is  to  drive  out  all  enclosed  air  which 
is  never  done  completely,  so  that  the  results  are  a  little  low,  yet 
are  satisfactory  for  the  most  practical  neels.  Also  the  boiling  tends 


to  loosen  any  small  fragments  not  removed,  which  also  lowers 
the  result.  The  most  accurate  way  is  to  place  the  stone  in  -the  wa- 
ter under  the  receiver  of  an  air  pump  and  exhaust  the  air.  This 
can  be  done  in  the  more  complete  laboratories.  This  state- 
ment is  to  be  remembered :  the  weight  of  a  rock  is  proportional 
to  the  specific  gravity,  porousity,  and  water  content. 

c.  The  porousity  of  a  stone  is  obtained  in  the  above  measure- 
ment by  weighing  the  piece  thoroughly  saturated  with  water  im- 
mediately on  its  removal  from  the  water  in  which  it  was  suspend- 
ed.    This  gives  the  weight  of  the  dry  stope  plus  the  weight  of 
water  absorbed  in  the  pores  of  the  substance.     What  is  desired, 
the  porousity,  is  the  ratio  of  the  open  space  in  a  rock  to  its  total  vol- 
ume.   To  obtain  this  we  divide  the  weight  of  a  piece  by  the  weight 
of  the  same  material  which  would  just  fill  the  open  places.     The 
first  weight  of  the  dry  stone  is  already  known,  and  we  obtain  the 
second  by  multiplying  the  weight  of  water  absorbed  by  the  spe- 
cific gravity  of  the  whole.    The  great  importance  of  this  figure  has 
already  been  pointed  out,  particularly  in  regions  of  great  temper- 
ature variations  and  considerable  moisture.     A  stone  thoroughly 
seasoned,  however,  ordinarily  suffers  little. 

d.  The  effects  of  freezing  and  thawing  on  a  stone,  both  dry 
and  saturated  with  water  are  properly  tested  under  those  condi- 
tions most  nearly  coinciding  with  those  actually  encountered.  A 
cube  of  the  rock  may  be  exposed,  both  dry  and  wet,  to  the  chang- 
ing temperature  of  day  and  night  during  the  winter,  for  a  period 
of  at  least  a  month,  and  then  tested  for  loss  in  weight  and  strength. 
The  action  of  extreme  heat,  as  in  the  case  of  fire,  may  be  tested 
by  heating  a  fragment  to  redness  in  an  assay  muffle,  and  noting 
the  effect,  first,  on  cooling  slowly  and  second,  on  plunging  the  hot 
stone  into  cold  water.     The  loss  in  strength  is  tested  in  the  usual 
way. 

e.  Lastly,  but  not  least  important,  much  light  can  be  thrown 
on  all  the  above  qualities  of  a  building  material  by  examination 
under  a  microscope.     Sections  of  the  rock  are  ground  to  a  thick- 
ne&s  of  about  two  hundredths  of  a  millimeter,  and  mounted  on 
glass  slides.     An  examination  under  a  propery  designed  micro- 
scope shows  everything  about  the  minerals :  their  relative  abun- 
dance,   nature,    size,    and    mutual    relations.    Also,    texture    and 
even  structure  missed  in  all  the  other  methods  of  investigation, 
may  be  shown  in  this  way.     Yet  the  life  of  the  stone  might  de- 
pend  upon  these  very  things.   In  short,  a  microscopic  examina- 
tion puts  the  finishing  touches  upon  a  thorough  search  after  the 


qualities  of  a  building  material,  and  such  a  search  is  incomplete 
without  this  investigation. 


CHAPTER  IV 

BUILDING  STONES  OF  NEVADA 

In  actual  amount,  Nevada  is  well  supplied  with  rocks  which 
can  be  used  as  building  material.  At  present,  with  a  territory  only 
beginning  its  true  development,  comparatively  little  is  used,  and 
few  quarries  are  opened.  Were  the  following  list  taken  only  from 
those  actually  quarried,  a  poor  showing  would  be  made.  It  has 
been  the  aim  to  include  also  those  rocks  which  can  easily  be  made 
use  of  at  a  profit,  in  order  that  both  capital  and  attention  may  be 
attracted.  All  throughout  the  west,  a  region  of  first  class  building 
stones,  the  fact  remains  that  the  value  of  imported  stone  runs 
annually  into  the  hundreds  of  thousands  of  dollars.  The  reason 
seems  to  be  that  people  refuse  to  take  advantage  of  natural  op- 
portunities and  to  develop  their  own  resources,  largely  because 
imported  material  is  easy  to  obtain  and  is  less  common  than  home 
products.  It  is  true  that  the  commoner  uses  of  stone,  as  curbing, 
abutments  and  some  buildings,  are  supplied  by  materials  produced 
here,  but  for  the  finer  uses  a  very  large  percentage  of  imported 
stone  is  placed.  The  west  suffers  from  a  lack  of  red  granite  for 
ornamental  work,  as  in  monuments,  yet  there  is,  some  first  class 
rock  of  this  color  both  in  Nevada  and  California  which  should 
be  developed.  At  the  present  writing,  nothing  can  be  given  in  the 
way  of  figures  of  invested  capital,  costs  of  handling  stone,  wages, 
et  cetera,  for  the  simple  reason  that  they  are  not  obtainable.  Not 
one  quarry  in  the  state  is  working,  and  except  when  a  lot  of  stone 
is  needed  for  some  sudden  purpose,  no  work  is  ever  done.  Need- 
less to  say,  the  capital  invested  is  at  the  most  but  a  few  hundred 
dollars,  outside  the  value  of  the  land,  hence  is  not  important.  The 
location  and  the  possibilities  of  building  stones  are  the  most  val- 
uable part  of  what  follows.  Much  in  this  chapter  will  be  of  no 
immediate  value;  much  will  be  fragmentary,  for  it  is  difficult  to 
obtain  accurate  data  throughout.  Many  of  the  important  qualities 
of  a  stone  can  be  determined  only  after  a  quarry  face  has  been 
opened,  and  as  yet  the  University  is  not  equipped  with  a  testing 
machine,  hence  it  will  be  some  years  before  a  detailed  report  can 
be  published. 

The  rocks  will  be  mentioned  in  the  order  given  in  the  classi- 
fication in  chapter  II,  beginning  with  the  plutonic  igneous,  or,  as 
they  are  sometimes  called,  the  "granitic  rocks." 

PLUTONIC  OR  GRANITIC  ROCKS 

Under  this  division  there  are  several  important  stones  actu- 


ally  in  use,  and  others  with  first  class  possibilities.  And  in  class- 
ifying these  rocks  a  slight  difficulty  is  presented.  Such  rocks  are 
called  popularly  granites.  Some  of  them  are  granites ;  others  are 
not,  but  all  are  related.  The  geographical  belt  lying  on  the  east 
flank  of  the  Sierra  Nevada  and  along  the  foothills  is  characterized 
by  an  abundant  development  of  these,  all  more  or  less  connected 
in  origin,  yet  varying  from  those  properly  termed  granites  to 
those  of  dioritic  nature.  As  a  group,  chemically  they  stand  be- 
tween these  two  types  of  plutonics,  containing  an  excess  of  soda 
over  potash,  and  often  considerable  lime.  Some  contain  an  abun- 
dance of  free  quartz,  others  show  little  to  none.  As  any  petro- 
graphical  discussion  is  here  out  of  place,  only  a  few  remarks  of 
this  nature  will  be  presented  under  each  rock.  The  writer  hopes 
to  show  later,  in  a  petrographical  paper,  the  true  relationships  of 
the  granitic  rocks  of  this  western  portion  of  Nevada.  For  the 
present,  the  term  granite  will  be  used  exclusively  for  those  rocks  • 
showing  free  quartz. 

GRANITES. 

Laughtons  Station :  This  stone  occurs  in  the  immediate 
vicinity  of  Laughton's  Station,  to  the  north  of  the  Southern  Pa- 
cific Railroad  track,  about  five  miles  west  of  Reno.  Considerable 
amounts  of  rough  stone  have  been  taken  out  at  the  outcrop  di- 
rectly on  the  railroad,  but  no  real  quarry  face  has  been  opened. 
In  color  this  granite  is  a  medium  to  light  gray,  with  occasional 
splotches  of  a  darker  shade.  The  rock  is  abie  to  take  a  good  pol- 
ish, quite  in  contrast  to  the  rough  finish.  Considerable  joint 
structure  is  developed  on  a  large  scale,  sufficient  to  make  quarry- 
ing easy,  and  yet  not  enough  to  preclude  the  possibility  of  extract- 
ing large  blocks.  The  texture  is  of  medium  fineness,  or  grain, 
in  the  main  phase  of  the  stone,  but  varies  considerably.  The  nor- 
mal rock  has  much  more  white  mineral  than  dark,  but  often 
rounded  spots  occur  which  contain  a  much  larger  percentage  of 
black  constituents.  These  spots  are  at  times  thickly  interspersed 
throughout  the  main  mass ;  often  they  are  seen  as  isolated  dark 
centers  surrounded  by  many  feet  of  surface  of  the  normal 
variety.  The  minerals  to  be  seen  by  the  naked  eye  are  quartz/ 
feldspar  both  orthoclase,  the  potash  variety,  and  plagioclase,  the 
.soda-lime  variety,  brown  mica,  and  black  hornblende.  The  mica 
is  the  chief  dark  mineral  in  the  normal  rock,  but  hornblende  pre- 
ponderates in  the  dark  spots.  Under  the  microscope  the  orthoclase 
felspar  is  seen  to  be  in  crystals  much  larger  than  those  of  the  oth- 
er minerals,  and  is  also  greater  in  amount  than  the  plagioclase. 


The  quartz  is  not  in  great  percentage.  Little  or  no  pyrite  is  pres- 
ent. As  in  all  granite,  die  hardness  is  considerable.  The  rock 
is  rather  brittle,  and  the  crushing  strength  is  medium  for  a  gran- 
ite, the  variation  in  grain  lowering  this  value.  The  stone,  because 
of  its  location  on  the  railroad,  is  available  at  once  and  in  large 
amount.  The  railroad  owns  that  part  of  the  massi  now  quarried 
at  all,  and  can  furnish  vast  quantities  when  required.  Unless  a 
well  opened  quarry  should  show  a  more  uniform  grade  of  mater- 
ial, the  uses  of  the  stone  will  be  limited.  It  can  be  used  for  orna- 
mental work  if  no  variations  in  texture  are  present,  and  for  all 
the  more  common  demands,  such  as  foundations,  curbing,  walks 
and  the  like  it  will  give  satisfaction. 

Verdi :  In  the  vicinity  of  the  town  of  Verdi,  which  is  about 
ten  miles  west  of  Reno  on  the  Southern  Pacific  railroad,  consid- 
erable areas  of  granite  exist.  Much  of  it  is  directly  on  the  rail- 
road, south  of  the  town,  along  the  Truckee  river.  From  Verdi  to 
the  south  the  surface  rises  steeply  for  about  two  hundred  feet 
to  a  level  terrace  of  granite,  with  boulders  of  andesite  disjpersed 
over  it,  the  last  remains  of  an  extensive  flow.  Several  faults  oc- 
cur on  this  terrace,  with  resultant  rise  of  the  plutonic  rock  and 
increased  opportunity  for  quarrying.  No  quarrying  has  yet  been 
done,  but  the  possibilities  are  surely  worth  serious  consideration. 
There  are  two  types  of  granite  which  will  be  described. 

i.  This  first  type  of  rock  is  that  which  makes  up  most  of  the 
mass.  The  color  is  a  rich  dark  gray,  with  a  faint  trace  of  pink, 
giving  as  a  result  a  very  handsome  stone.  It  is  able  to  assume  a 
high  polish,  showing  quite  dark  in  comparison  with  the  rough 
surface.  As  no  quarry  face  has  been  opened,  nothing  can  be 
stated  about  the  structure  of  the  rock,  except  that  as  some  fault- 
ing has  occurred,  joint  planes  are  probably  developed.  From  the 
outcrops  existing,  the  texture  appears  fairly  constant,  there  being 
a  slight  change  in  color  in  widely  separate  localities.  However, 
the  stone  seems  to  be  remarkably  free  from  imperfections  in  this 
respect.  The  minerals  present  are  quartz,  feldspar,  mostly  ortho- 
clase,  hornblende,  and  mica.  The  hornblende  is  the  more  plentiful 
of  the  dark  constituents.  The  pinkish  tint  is  due  to  the  color  of 
the  orthoclase,  which  is  a  pleasing  flesh  color.  Quartz  is  not  very 
plentiful,  whereas  the  black  minerals  are,  hence  the  dark  color  of 
the  whole.  The  sulphides  are  very  small  in  amount.  The  hard- 
ness and  toughness  are  perhaps  a  little  higher  than  in  the  Laugh- 
ton  stone,  and  sufficient  for  all  purposes.  But  like  the  Laughton 
stone,  it  is  so  situated  that  it  is  available  at  any  time  with  lowest 


possible  cost  of  handling.  An  opening  to  exhibit  the  character  of 
the  mass  is  all  that  is  needed  to  show  it  up  properly.  For  monu- 
mental work  as  well  as  for  all  the  best  uses,  this  granite  should 
find  a  ready  market,  if  present  indications  have  much  weight. 

2.  The  second  variety  of  granite  from  Verdi  is  found  at 
present  only  in  boulders  lying  on  the  worn  surface  of  the  other. 
It  undoubtedly  occurs  as  veins  in  the  main  mass,  and  should 
properly  be  called  a  pegmatite.  These  dykes  must  be  of  large  size, 
because  of  the  dimensions  of  the  largest  fragmens  derived  from 
them.  A  quarry  is  necessary  to  outline  any  facts  about  the  mat- 
ter. The  color  is  either  a  light  red  ground  through  which  are 
irregularly  dispersed  black  shining  crystals  of  tourmaline,  or 
more  rarely,  a  white  ground  with  the  dark  mineral.  The  general 
effect  is  very  pleasing  to  the  eye,  presenting  a  sharp  contrast  to 
the  other  variety  of  granite.  The  texture  is  peculiar,  for  the  min- 
erals are  not  at  all  regularly  distributed.  The  mass  of  the  rock 
is  made  up  of  quartz  and  feldspar,  usually  redish  orthoclase, 
through  which  occur  bunches  of  black  tourmaline  crystals.  The 
quartz  and  feldspar  are  of  fine  grain,  while  the  black  mineral,  in 
coarser  crystals,  is  in  spots  in  size  from  a  quarter  of  an  inch  up 
to  a  foot  or  more.  The  stone  will  take  a  high  polish,  differing 
little  from  the  unfinished  surface  in  shade.  It  should  meet  with 
favor  for  some  kinds  of  ornamental  work,  as  well  as  for  building 
material,  if  it  can  be  obtained  in  large  enough  amount. 

Washoe:  This  ganite  outcrops  west  of  the  old  town  of 
Washoe,  on  the  Virginia  and  Truckee  railroad,  and  is  a  part  of 
the  great  granite  mass  occurring  at  the  east  base  of  the  Sierra.  A 
quarry  is  opened  about  a  mile  west  of  the  town,  on  land  owned  by 
Mr.  John  Barrett,  the  stone  cutter  of  Reno.  Not  a  great  deal  of 
work  has  been  done,  yet  the  stone  has  been  shown  to  be  of  fairly 
uniform  color  and  grain.  The  color  is  a  medium  dark  gray,  with 
a  very  faint  pinkish  tinge,  lighter  than  the  Verdi  rock.  There  ap- 
pear to  be  few  or  no  imperfections  in  structure  debarring  the  ex- 
traction of  large  pieces  for  use,  but,  in  common  with  most  of  these 
rocks  of  the  region,  the  texture  varies  somewhat.  At  times 
splotches  of  dark  constituents  occur  to  mar  the  even  aspect  of  the 
surface.  Careful  selection,  however,  should  eliminate  this  evil. 
A  good  polish  is  taken,  quite  dark  compared  with  the  unfinished 
stone.  The  minerals  are  quartz,  both  varieties  of  feldspar,  mica 
and  hornblende.  The  two  dark  constituents  are  about  equal  in 
amount  while  the  quartz  is  sparingly  distributed.  The  sulphide 
minerals  are  rare,  as  in  all  of  these  rocks.  Both  hardness  and 


toughness  are  fairly  high,  and  should  improve  as  deeper  cuts  are 
made  in  the  quarry.  This  stone  is  not  quite  so  readily  available  as 
those  already  mentioned,  as  a  haul  of  a  mite  to  the  railroad  is 
necessary.  At  present  the  granite  is  used  for  monuments  and 
ornamental  purposes  by  Mr.  Barrett. 

Nearer  the  railroad,  and|  in  fact,  directly  on  it,  is  an  occur- 
rence of  volcanic  and  plutonic  boulders,  in  which  are  some  of 
granite.  This  stone  is  the  same  as  the  Washoe  granite  just  men- 
tioned, and  is  quarried  by  the  railroad  for  use  in  culverts,  abut- 
ments, and  the  like.  Such  a  source  is,  necessarily,  limited  in  ex- 
tent, yet  it  does  sufficiently  well  for  immediate  needs.  And  it  may 
be  well  to  note  here  that  most  of  the  granite  now  used  in  and  about 
Reno  for  curbing,  mounting  blocks,  and  such  commoner  demands, 
is  obtained  from  the  vast  quantity  of  boulders  existing  in  the 
river  wash  covering  much  of  the  adjacent  territory.  It  is  needless 
to  remark  upon  the  cheapness  of  this  source,  yet  the  best  quality 
of  material  cannot  be  furnished  in  such  a  way,  so  that  the  ultimate 
cheapness  is  lessened.  Only  a  well  opened  quarry  will  deliver 
the  best  stone,  and  when  substantial,  long-lived  buildings  are  to  be 
constructed,  field  boulders  should  never  be  used  unless  of  excep- 
tional size. 

Ophir:  This  rock  is  well  exposed  at  Ophir,  about  a  mile 
northwest  of  Franktown,  on  the  Virginia  and  Tnickee  railroad. 
A  little  preliminary  quarrying  has  been  done  at  a  point  just  south 
of  the  wood  flume,  on  the  small  creek  here  draining  down  from  the 
mountains.  The  stone  rises  up  about  a  hundred  feet  above  the 
creek,  giving  some  opportunity  for  working.  As  yet  the  solid  mass 
of  the  granite  has  not  been  reached,  the  quarrying  has  been  done  in 
the  more  or  less  broken  surface  material.  The  color  is  the  lightest 
of  all  those  described  being,  in  the  average,  a  very  light  gray. 
Some  varieties,  small  in  amount,  are  darker  in  shade.  A  good 
polish  is  possible,  which  is  little  darker  than  the  rough  surface. 
Jointing  is  well  developed,  insuring  ease  in  quarry  work  while 
not  preventing  the  extraction  of  large  blocks.  In  texture  the  rock- 
as  a  whole  varies  considerably,  though  the  main  mass  is  fairly 
constant.  Normally  the  crystals  of  the  component  minerals  are 
fine  in  grain,  with  longer  black  crystals  sparingly  distributed 
throughout.  The  minerals  of  fine  even  grain  are  quartz,  both 
feldspar  and  brown-black  mica,  the  larger  black  crystals  are  horn- 
blende. The  quartz  is  very  plentiful,  giving  almost  a  glassy  luster 
to  the  rock.  Also,  many  small  grains  of  a  yellowish  mineral  are 
dispersed  rather  plentifully.  The  other  varieties  are  due  to  the 


change  in  the  relative  amounts  and  kinds  of  the  minerals  present. 
Some  show  an  abundance  of  large  shining  mica  flakes  with  little 
or  no  hornblende ;  some  show  much  hornblende  with  no  mica ;  and 
others  show  a  great  amount  of  clear  colorless  quartz.  These,  how- 
ever, are  in  small  amount.  This  granite  is  very  hard,  but  more 
brittle  than  the  others.  It's  availability  is  apparent,  being  less  than 
a  mile  from  the  railroad.  It's  possible  uses  are  limited  by  it's  vari- 
ation in  texture  to  the  commoner  ones,  such  as  curbings,  mount- 
ing blocks,  foundations,  and  pavements,  though  it's  light  color 
might  find  favor  for  contrast  in  monumental  work. 

Lakczncw:  This  stone  is  well  shown  in  the  railroad  cuts 
south  of  the  station  of  Lakeview,  three  miles  northwest  of  Carson 
on  the  Virginia  and  Truckee  railroad.  The  railroad  grade  winds 
around  a  hill  composed  chiefly  of  this  rock,  thus  making  it  pos- 
sible to  obtain  vast  quantities  at  a  minimum  cost.  Xo  quarrying 
of  any  sort  has  been  done,  as  the  stone  is' not  of  the  best  quality 
for  building  needs.  The  color  is  a  light  gray,  similar  to,  but 
darker  than  the  Ophir  granite.  In  the  exposed  outcrop  many  lit- 
tle dots  of  red  are  to  be  seen  on  careful  inspection.  The  mass 
of  the  rock  is  quite  faulted  and  jointed,  but  blocks  of  large  size  can 
be  taken  out,  judging  by  the  weathered  portion.  The  texture  is 
rather  coarse  in  appearance,  because  of  the  large  size  of  the  horn- 
blende crystals ;  the  light  colored  constituents  are  of  finer  grain. 
The  minerals  are  quartz,  feldspar,  again  both  kinds,  with  a  slightly 
larger  percentage  of  othoclase,  hornblende  and  mica.  The  horn- 
blende is  the  chief  dark  constituent.  Quartz  in  nominal  amount. 
A  considerable  number  of  small  grains  of  a  yellowish  mineral 
are  present,  as  in  the  Ophir  stone.  One  other  substance  is  worthy 
of  notice  ;  the  mineral  magnetite,  which  shows  quite  plentiful  under 
the  microscope.  Such  a  rock  as  this  is  limited  in  usefulness  to 
the  commoner  demands,  and  it  is  also  possible,  on  account  of  the 
mineral  content,  to  use  it  as  a  road  metal.  It's  vast  amount,  easy 
or"  access,  its  small  mica  percentage  and  its  comparatively  large 
percentage  of  iron,  make  it  easily  possible  that  it  might  prove  a 
success  as  a  material  for  macadamized  roads. 

Carson  Prison  :  On  the  Prison  Hill  as  it  is  called,  a  granite 
similar,  or  the  same,  outcrops  from  beneath  the  andesite  flows. 
This  locality  is  not  on  the  line  of  the  railroad,  but  is  easily  ap- 
proached by  teams.  If  the  stone  proves  a  good  road  metal,  this 
would  make  a  good  locality  to  furnish  material  for  those  parts  of 
the  region  nearby. 

:     Near  the  town  of  Liming,  in  Esmeralda  county 


and  five  miles  from  the  line  of  the  Carson  and  Colorado  railroad, 
there  is  an  occurrence  of  a  fine  grained  white  granite.  No  reai 
quarrying  has  been  done,  and  only  a  small  amount  of  stone  has 
been  extracted.  Small  pieces  show  a  finer  grain  than  in  the  other 
granites  described,  and  exhibit  a  contrast  with  them.  The  land 
and  stone  is  owned  by  Mr.  Lindsay,  of  Carson,  who  has  the  stone 
for  sale,  as  well  as  for  his  own  use  in  building  work. 

Mason  Valley :  This  stone  occurs  near  Mason  Valley,  in 
Hudson  Pass,  Lyon  county,  about  eighteen  miles  from  the  Car- 
son and  Colorado  railroad.  As  with  most  of  the  other  rocks,  no 
quarrying  of  any  amount  has  been  done,  ami  the  stone  awaits  a 
market.  The  color  is  rather  striking,  being  a  light  mottled  pink- 
gray.  On  close  inspection  three  distinct  colors  present  themselves, 
due  to  the  different  minerals ;  white,  pink  and  dark  green.  The 
polished  surface  brings  these  out  well,  and  presents  a  considerable 
and  pleasing  contrast  with  the  rough  finish.  The  grain  is  medium 
and  even,  with  an  occasional  large  white  crystal.  The  polish 
brings  out  clearly  most  of  the  component  minerals.  To  the 
naked  eye  no  quartz  is  present,  and  the  rock  looks  like  a  syenite, 
or  that  rare  rock  standing  between  a  syenite  and  a  diorite — a 
monzonite.  The  minerals  easily  seen  are  feldspar,  including 
stout  pink  crystals  of  orthoclase,  and  long  white  crystals  of  plag- 
ioclase.  Under  the  microscope,  quartz  is  apparent,  making  the 
rock  a  granite  though  a  basic  one.  Both  hardness  and  toughness 
are  high.  The  stone  is  not  as  available  as  could  be  desired,  yet  its 
color  and  other  qualities  are  such  that  its  value  is  high.  It  can 
be  used  for  monumental  work,  and  buildings,  and  should  find  i 
ready  market.  The  owner  of  the  present  "quarry"  is  Mr.  Lindsay, 
of  Carson. 

Winncmncca:  Two  varieties  of  granite  are  used  in  Winne- 
mucca.  The  first  is  quarried  twelve  miles  to  the  north  of  the  town, 
and  hauled  in  by  teams.  It  is  a  medium  light  gray  stone,  taking 
a  fine  polish,  and  is  sufficiently  good  for  the  best  class  of  work. 
The  grain  is  of  medium  coarseness,  with  little  variation  in  color 
or  mineral  content.  The  minerals  are  the  usual  ones  already  men- 
tioned, with  not  a  great  deal  of  quartz.  By  way  of  illustrating 
availability,  some  figures  of  cost  of  hauling  for  this  stone  will  be 
.given,  which  are  fairly  good  for  others  removed  from  the  railroads. 
A  trip  from  Winnemucca  to  the  quarry  and  return  occupies  two 
days,  with  a  large  wagon.  Seventy-five  cubic  feet  of  stone  are 
hauled  at  a  trip,  for  which  eighteen  dollars  are  charged.  This 
stone  has  found  some  favor  for  monuments  in  the  town,  and  can 


be  used  for  ornamental  and  construction  work.  Mr.  Joe  Pasquale 
is  owner. 

The  second  granite  used  in  Winnemucca  is  taken  from  boul- 
ders found  on  the  lower  slopes  of  the  mountain  bearing  the  same 
name  as  the  town.  In  color  and  general  appearance  it  is  much 
like  the  first,  but  takes  a  poorer  polish.  It  also  has  found  some 
demand  for  monuments  and  buildings,  but  is  inferior  to  the  first 
because  of  longer  exposure  in  fragments.  However,  it  is,  well 
adapted  to  all  the  commoner  uses. 

Elko :  Much  granite  exists  both  to  north  and  south  of  the 
town  of  Elko  but  at  some  distance.  At  present  one  variety  is 
quarried,  and  used  in  the  town  for  nearly  all  purposes.  This  rock 
comes  from  a  spot  about  thirty  miles  north,  necessitating  a  long 
haul.  The  distance  from  the  railroad  limits  its  use  and  market, 
for  when  a  quarry  is  well  opened  on  the  line  of  the  railroad,  as  can 
be  easily  done,  at  a  place  like  Verdi,  such  a  stone  will  be  driven 
from  use  by  it's  cheaper  rivals.  It  is  possible  to  find  some  first- 
class  monumental  granites  in  the  region  about  Elko.  And  there 
are  many  other  possible  stones.  Granite  is  plentiful  at  Steamboat 
Springs,  and  more  at  Verai,  up  Dog  Creek  Canyon.  Likewise 
in  the  eastern  part  of  the  state  there  is  much  similar  stone,  most 
of  it  unknown  in  value  and  qualities.  But  for  some  years  only 
the  most  valuable  granites  existing  away  from  transportational 
facilities  can  be  available,  because  of  the  wealth  of  easily  obtained 
poorer  stone  outcropping  directly  on  the  railroad  lines. 

DIORITES 

Virginia  City :  The  mass  of  Mt.  Davidson,  upon  whoste 
eastern  flanks  Virginia  City  lies,  is  chiefly  of  a  dioritic  rock.  It  is 
not  urged  that  this  rock  would  make  a  first-class  building  material, 
for  it's  color  is  a  somber  gray,  it's  grain  fine,  and  the  whole  aspect 
uninviting.  It  is  mentioned  in  tnis  place  because  of  its  possible 
use  as  a  road  metal.  It's  constituents  are  feldspar  and  hornblende, 
with  usually  some  iron  pyrite.  The  texture  is  one  of  interlocking 
crystals,  causing  very  great  toughness.  There  are  several  phases 
of  the  stone,  each  with  it's  own  color  and  general  appearance. 
The  summit  outcrop  develops  a  gray  granite  looking  rock;  the 
tunnels  and  crosscuts  in  the  mines  often  show  a  much  darker  va- 
riety. For  a  road  metal,  the  binding  power  should  be  good,  while 
the  toughness  will  be  vouched  for  by  every  miner  who  has  driven 
a  drill  into  it.  As  mentioned  in  the  chapter  on  road  metal,  the 
rock  may  prove  easily  a  most  valuable  one  for  use  on  roads  under- 
lying heavy  traffic. 


Ill 


Beckwith  Pass:  This  rock  is  found  near  Beckwith  Pass,  i 
California,  but  as  its  development  must  come  through  Nevada,  it 
is  here  included.  Like  all  the  granite  rocks,  it  exists  in  practi- 
cally unlimited  quantity.  A  little  quarrying  has  been  done,  suf- 
ficient to  show  up  the  stone  fairly  well.  The  color  is  a  very  dark 
gray,  darker  than  the  Verdi  granite,  which  it  somewhat  resembles 
in  appearance.  It  takes  a  perfect  polish,  which  does  not  present 
a  great  contrast  to  the  rough  surface,  as  the  stone  is  essentially  so 
dark.  The  grain  is  of  medium  coarseness,  and  very  constant; 
the  stone  is  quite  free  from  irregularities  of  all  sorts.  The  min- 
erals present  are  plagioclase  feldspar,  with  mica  and  hornblende 
in  nearly  equal  amount.  Black  magnetite  also  occurs.  The  hard- 
ness and  toughness  are  fairly  high.  It  is  yet  necessary  to  haul 
the  stone  some  distance  to  the  railroad,  which  militates  slightly 
against  it's  use.  With  the  advent  of  the  proposed  Western  Pa- 
cific railroad,  this  difficulty  will  be  largely  eliminated.  The  quar- 
ry now  operated  is  owned  by  Mr.  John  Barrett,  of  Reno,  who  has 
been  mentioned  as  owning  a  Washoe  stone.  This  diorite  is  now 
used  for  monumental  work  entirely,  and  is  well  fitted  for  all  the 
best  class  of  uses.  It  also  might  prove  a  valuable  road  material, 
for  which  the  chippings  and  waste  could  find  a  market. 

VOLCANIC  ROCKS 

RHYOUTUS 

There  are  two  stones  used  in  Nevada  which  are  classed  with 
this  group  of  rocks.  Both  are  from  the  region  just  south  of  Vir- 
ginia City,  near  the  American  Flat  Tunnel  on  the  line  of  the  Vir- 
ginia and  Truckee  railroad,  in  Lyon  county.  Both  are  quartz- 
porphyrites  in  a  general  sense,  though  there  are  variations  from 
a  true  quartz-porphyry  or  rhyolite,  to  a  quartz-andesite,  or  dacite, 
based  on  the  nature  of  the  included  feldspars.  In  detail  these 
rocks  are  as  follows  : 

i.  The  first  stone  is  quarried  from  the  great  mass  covering 
many  acres,  at  a  point  on  the  railroad  one- fourth  of  a  mile  west  of 
the  American  Flat  tunnel.  The  color  is  a  not  unpleasant  yellow- 
ish white,  a  suitable  shade  for  a  dry,  dusty  climate.  The  texture 
is  porphyritic,  and  even  throughout  large  volumes.  On  close  in- 
spection the  color  is  seen  to  be  due  to  the  ground  mass ;  while  the 
crystals  showing  are  chiefly  clear  quartz,  and  white  feldspar. 
Some  small  grains  of  iron  bearing  minerals,  as  mica,  are  present 
in  small  amounts.  The  general  effect  is  good,  a  little  different 
from  the  usual  run  of  stones.  The  rather  large  glassy  quartz 
grains,  particularly,  give  the  rock  a  distinct  individuality.  The 


hardness  is  high;  the  toughness  a  little  less,  and  both  rank  with 
the  best.  Much  resistance  to  atmospheric  changes  is  given,  so  that 
long  life  to  a  structure  of  this  material  is  assured.  The  quarry 
cut  is  directly  on  the  railroad,  so  that  any  amount  needed  can  be 
easily  obtained,  the  railroad,  of  course,  owning  the  land.  This 
stone  was  much  used  in  the  early  days  on  the  Comstock,  chiefly 
for  foundations.  It  shows  no  evidence  of  change  where  so  used. 
The  railroad  now  constructs  of  it  abutments,  culverts,  retaining 
\valls  and  other  similar  structures. 

2.  The  second  quartz-porphyry  is  quarried  five-eights  of  a 
mile  east  of  the  tunnel  already  mentioned.  The  color  in  the  mass 
is  a  medium  dark  purplish,  which  color  is  a  not  inconsiderable 
factor  in  the  worth  of  the  stone.  The  texture  like  that  of  the 
other,  is  porphyritic,  with  well  developed  crystals  of  quartz,  feld- 
spar, and  dark  mica.  The  color  is  due  to  the  purplish-gray  ground 
mass,  in  which  the  other  minerals  show  distinctly.  The  main 
difference  between  these  two  rocks  is  in  the  color,  and  the  increase 
In  the  amount  of  mica  in  the  purplish  variety.  This  latter  stone  is 
decidedly  pleasing  to  look  upon,  and  should  find  favor  for  build- 
ings. It's  hardness,  toughness,  and  other  characteristics  are 
identical  with  those  of  the  first  of  these  rocks,  and  likewise  it  is 
quarried  by  the  railroad  and  used  in  some  of  it's  culverts  and 
abutments.  It  has  been  used  in  one  of  the  railroad  crossings  at 
Steamboat  Springs,  and  makes  a  fine  appearance. 

ANDESITES 

There  are  several  quite  prominent  building  stones  under  this 
rock  group,  including  some  of  great  promise.  As  the  demand  for 
such  materials  of  construction  increases,  they  should  all  find  ready 
markets,  particularly  as  they  are  easy  of  access  and  near  the  cen- 
ters of  population. 

Southwest  of  Row:  This  stone  is  the  one  used  largely  in 
die  erection  of  the  new  Carnegie  Library  Building  in  Reno.  It  is 
locally  called  a  sandstone.  It  comes  from  one  of  the  large  andesite 
flows  which  bathed  the  lower  eastern  flanks  of  the  Sierra  in  recent 
geological  time.  The  quarry  is  situated  at  a 'point  about  four 
miles  southwest  of  Reno  in  an  air  line,  though  nearly  two  miles 
further  by  road.  The  work  here  has  just  begun,  and  is  due  to 
the  construction  of  the  building  just  mentioned.  Enough  has  been 
accomplished,  however,  to  show  some  of  the  larger  characteristics. 
The  quarry  shows  well  the  flow  structure  of  the  mass ;  the  planes 
of  motion  lie  nearly  horizontal,  greatly  facilitating  the  extraction 
of  large  blocks.  On  this  account,  the  cost  of  quarrying  is  very 


low,  aided  also  by  the  absence  of  any  overburden,  or  surface  waste 
material,  beside  a  few  feet  of  rocky  soil.  The  color  is  a  medium 
light  red  or  red-gray,  similar  to  but  redder  than  the  tint  of  the 
quartz-porphyry  from  Virginia  City.  The  texture  is  porphyritic, 
showing  white  feldspar  crystals  with  smaller  ones  of  mica  and 
hornblende,  in  the  red-gray  ground  mass.  The  white  feldspar  is 
all  that  shows  on  a  cursory  examination,  and  as  much  of  this  min- 
eral is  present,  the  popular  term  sandstone  has  been  employed. 
These  more  or  less  lath  shaped  crystals  of  feldspar  are  arranged 
roughly  parallel  along  the  flow  planes.  The  red  color  of  the 
ground  mass  owes  it's  nature  to  the  decomposition  of  the  iron* 
bearing  ground  mass,  with  the  resultant  deposition  of  iron  oxide 
throughout.  The  effect  produced  is  fair  to  look  upon,  but  the 
stone  is  weakened  thereby.  The  hardness  and  toughness  are  low 
for  a  rock  of  this  type,  and  are  little  better  than  in  .an  average 
sandstone.  It  would  crush,  probably,  at  a  pressure  of  about  six 
thousand  pounds  per  square  inch.  This  is  sufficient  for  all  or- 
dinary  demands,  but  not  enough  for  the  very  largest  buildings 
now  erected.  It  will  withstand  much  in  the  nature  of  temperature 
changes,  as  will  all  the  rocks  of  this  group. 

Being  situated  near  Reno,  it  should  be  used  in  many  more 
buildings  to  be  erected  in  the  near  future.  It's  general  appearance 
counts  strongly  in  it's  favor. 

On  the  western  side  of  the  ridge  on  which  the  above  quarry 
is  situated,  is  a  second  outcrop  of  the  same  rock.  There  is  a  dif- 
ference, however,  for  here  the  red  color  is  replaced  by  a  gray,  due 
to  the  non-oxidation  of  the  mass.  The  other  features  are  the 
same,  except  that  the  lasting  qualities  are  much  better.  The  two 
stones  are  in  pleasing  contrast,  and  will  undoubtedly  find  favor  in 
a  short  time. 

Huf faker:  There  are  two  varieties  of  andesite  at  this  point, 
five  miles  south  of  Reno  on  the  Virginia  and  Truckee  railroad. 
The  railroad  here  skirts  the  foot  of  a  rather  low  hill,  on  which  out- 
crop the  rocks  in  question.  They  are  both  part  of  the  same  mass. 

The  first  is  a  red  stone,  a  shade  darker  than  the  library  ande- 
site. It  forms  most  of  the  surface  material  and  can  be  obtained 
in  quite  large  amount.  No  quarry  face  has  been  opend,  so  that 
nothing  can  be  told  about  is  structure.  It  has  no  flow  planes  like 
the  first  mentioned  andesite.  It  is  porphyritic  in  texture,  showing 
well  formed  crystals  of  black  hornblende,  red  'discolored  lath 
shaped  crystals  of  feldspar,  and  all  in  the  red  ground  mass.  The 
hornblende  is  quite  plentiful,  the  feldspar  is  about  equal  in  amount, 
but  decomposed  and  reddened  as  is  the  ground  mass.  The  hard- 


ness  is  medium,  the  toughness  somewhat  less.  The  availability 
of  the  material  is  a  strong  point  in  it's  favor,  as  it  outcrops  less 
than  a  hundred  feet  from  the  railroad  track.  It  is  on  the  Huffa- 
ker  ranch,  and  has  been  used  locally  to  some  extent. 

The  second  variety  is  a  granitic  looking  rock,  and  by  the  av- 
erage individual  would  possibly  be  called  a  granite.  It  outcrops 
on  the  same  hill  as  the  other,  and,  due  to  the  fact  that  less  decom- 
position has  taken  place,  lacks  a  red  color.  It  is  a  medium  light 
gray  stone,  apparently  showing  quartz,  feldspar,  and  hornblende. 
Careful  study,  with  and  without  the  microscope,  show  it  to  DC 
a  truly  prophyritic  rock,  of  medium  grain  and  even  texture.  The 
minerals  in  well  formed  crystals  are  white  feldspar,  black  horn- 
blende, and  a  few  flakes  of  mica,  set  in  a  glassy,  colorless,  ground 
'mass.  It  is  this  glass  which  has  the  appearance  of  quartz.  The 
general  aspect  of  the  rock  is  decidedly  in  its  favor.  As  no  real 
quarrying  has  been  done,  and  no  thoroughly  unaltered  rock  ex- 
posed, it's  other  qualities  are  not  known.  From  it's  construction 
it  must  be  a  very  hard  though  perhaps  brittle,  stone.  The  Huffa- 
ker  residence,  a  large  two  story  structure,  is  made  of  this  material, 
which  shows  no  change  in  its  thirty  years  of  service.  These  two 
andesites  are  worthy  of  careful  investigation  and  some  work  done 
to  exploit  them. 

Pulton's  Quarry:  The  rock  exposed  in  this  place  exists  to 
the  north  of  Reno,  over  considerable  territory.  The  quarry  itself, 
in  the  best  material,  is  about  two  miles  north  of  the  University 
campus,  just  above  the  line  of  the  Nevada,  California  and  Oregon 
railroad.  What  work  has  been  done  is  all  on  the  surface;  no 
quarry  face  has  been  well  opened.  The  color  is  a  light  greenish 
gray  in  the  mass,  and  a  restful  one  to  the  eyes,  especially  in  the 
glare  of  the  sunlight  in  a  hot,  dry  climate.  The  rock  is  rather 
strikingly  porphyritic  on  close  inspection,  though  of  even  appear- 
ance at  a  little  distance.  Large  glassy  feldspar  crystals  half  an 
inch  in  length  are  frequent.  Also,  many  flakes  of  dark  mica  are 
present,  with  a  little  hornblende,  and  all  set  in  the  compact,  green- 
ish-gray ground  mass.  In  selected  pieces  the  texture  is  fairly  con- 
stant, but  as  a  mass  much  variation  occurs.  Inclusions  of  other 
materials  are  found,  and  small  cavities  lined  with  materials  are 
at  times  plentiful,  so  that  careless  work  may  result  in  unsightly 
spots  in  buildings.  The  hardness  and  toughness  are  fair,  and  the 
resistance  to  weather  changes  is  good.  As  it  is  on  the  railroad, 
it's  availability  is  excellent,  and  there  is  a  vast  quantity  in  sight. 
The  stone  has  been  used  considerably  in  Reno.  Several  of  the 
newer  University  buildings  contain  it,  as  the  gymnasium  and 


Lincoln  Hall,  and  a  few  structures  in  the  business  part  of  town  are 
made  wholly,  or  nearly  so,  of  the  material.  It's  greenish  tinge 
gives  a  pleasing  aspect  to  the  buildings  containing  it.  Another 
possible  use  is  that  of  road  metal.  In  the  search  for  such  mater- 
ial soon  to  come,  a  test  upon  the  rock  would  not  be  ill  advised. 

Virginia  City :  About  two  miles  to  the  east  of  the  old  town  of 
Virginia  City  runs  a  ridge  approximately  north  and  south.  Sugar 
Loaf  peak  is  part  of  this  ridge,  which  is  cut  in  two  by  Six  Mile 
Canyon  and  Creek.  An  andesitic  rock  forms  this  feature  of  the 
topography,  furnishing  one,  and  able  to  furnish  two,  stones  for 
building  purposes. 

The  first  of  these  is  quarried  at  a  point  just  east  of  the  Bruns- 
wick Lode,  on  the  east  side  of  a  small  hill  rising  from  the  ridge. 
Considerable  rock  has  been  taken  out  here,  yet  in  a  more  or  less 
careless  manner,  and  no  well  cut  face  is  shown.  The  structure  of 
the  mass  is  quite  remarkable.  Rock  columns  averaging  two  feet 
or  more  in  diameter  compose  the  whole,  like  a  bundle  of  sticks 
laid  carefully  parallel  to  one  another.  These  columns  pitch  to  the 
northwest  at  a  low  angle,  aiding  very  materially  the  quarrying1. 
This  stone  is  the  most  striking  in  appearance  of  all  those  describ- 
ed in  these  notes,  and  is  almost  beautiful.  Any  one  word  will  fail 
properly  to  give  the  color,  for  the  texture  his  given  the  rock  a 
mottled  aspect.  This  texture  is  porphyritic,  and  large  roughly 
rounded  feldspar  crystals  often  half  an  inch  across,  with  smaller 
prisms  of  hornblende  and  flakes  of  dark  mica  appear  in  a  blue- 
gray,  or  steel  blue  ground  mass.  The  feldspar  is  quite  glassy, 
much  in  contrast  to  the  lusterless  colored  ground.  There  is  some 
variation  in  texture,  which  must  be  guarded  against  by  selecting 
only  the  best.  Frequently  small  inclusions  with  slightly  differ- 
ent color  and  grain  occur,  which  spoil  the  even  effect  of  the  whole. 
The  hardness,  toughness,  and  other  characteristics  are  good,  and 
need  little  consideration  under  ordinary  circumstances.  The  stone 
is  easily  obtained,  the  quarry  being  less  than  two  miles  from  the 
railroad,  and  an  easy  haul  will  deliver  it  at  the  station.  It  was 
used  extensively  in  the  early  days  of  the  town  for  foundations  for 
large  machinery.  As  it  yet  remains  in  place,  one  can  see  how  well 
it  stands.  To  state  that  it  makes  a  beautiful  appearance  does  not 
seem  like  exaggeration. 

The  second  variety  of  these  andesites  occurs  in  Sugar  Loaf, 
and  in  the  exposed  places  in  the  immediate  vicinity.  It  has  not 
yet  been  quarried  nor  used.  A  fine  exposure  is  present  to  the 
southwest  of  the  road  in  Six  Mile  Canyon  just  where  the  bridge 
spans  the  creek  at  the  base  of  Sugar  Loaf.  This  rock  is  very 


similar  to  the  first,  yet  distinct  in  its  general  appearance.  The 
ground  mass  is  a  very  light  gray,  with  a  faint  tinge  of  blue,  and 
the  well  formed  minerals  are  white  feldspar,  in  smaller  crystals 
than  in  the  first  phase,  with  black  hornblende  more  plentiful  than 
before,  and  a  little  dark  mica.  The  other  qualities  are  about  the 
same  as  those  of  the  first  variety,  and  are  good.  A  little  harder 
pull  by  team  is  required  to  land  it  at  the  railroad  yards,  yet  this 
will  not  count  much  against  it.  As  far  as  known,  this  stone  has 
never  been  worked,  but  it  would  make  a  very  good  building  mater- 
ial. 

TUFFS 

There  are  three  of  these  valuable  building  stones  now  in  use 
in  the  state.  They  are  softer  than  the  average  consolidated  tuff, 
yet  this  lack  does  not  prevent  their  being  used  in  many  important 
ways.  They  fill  a  want  for  certain  kinds  of  materials  better  than 
any  other  stone,  and  at  times  rank  with  the  best  sandstones. 

Mcrrimac  Station :  This  tuff  outcrops  in  the  Virginia 
Range  in  the  canyon  of  the  Carson  river,  at  Merrimac  Station, 
on  the  line  of  the  Virginia  and  Truckee  railroad.  This  point  is  a 
few  miles  east  of  Empire,  andvwithin  easy  reach  of  all  important 
points.  The  quarry,  owned  by  Mr.  J.  W.  Adams,  of  Carson,  is  on 
the  south  bank  of  the  river,  and  is  one  of  the  very  few  well  opened 
ones  in  Nevada.  The  color  of  the  stone  is  a  light  pink,  almost  a 
flesh  color,  and  does  not  vary  throughout  the  mass.  As  it  is  com- 
posed of  volcanic  ashes,  with  some  mineral  fragments,  it's  texture 
might  be  taken  to  indicate  a  very  fine  grained  sandstone.  The 
fragmental  character  is  clearly  shown,  and  the  absence  of  strati- 
fication planes  or  layers  indicates  to  the  unaided  eye  the  nature  of 
the  material.  The  ash  is  largely  glass,  in  minute  fragments', 
in  which  are  imbedded  angular  pieces  of  mica,  quartz,  and  feld- 
spar in  small  amount.  The  grain  is  very  even  for  such  a  stone, 
and  it's  general  effect  is  very  good.  In  hardness  and  toughness 
it  stands  low,  about  equal  to  a  soft  sandstone,  too  low  to  warrant 
it's  use  under  much  stress.  It  tempers  a  little  on  standing,  but 
not  sufficient  to  raise  much  it's  strength.  It  is  rather  porous,  as 
are  all  the  tuffs,  yet  withstanding  temperature  changes  well,  be- 
cause of  it's  internal  structure.  It  has  been  used  very  largely  in 
and  about  Carson  and  Reno,  chiefly  for  copings,  cornices,  lintels, 
arches,  and  such  others  requiring  little  strength.  When  used  with 
brick,  a  very  pleasing  contrast  is  presented,  as  is  done  with  any 
other  material  harmonizing  with  it  in  color.  The  Gymnasium 
and  Lincoln  Hall  of  the  University  Buildings  both  contain  it, 
some  brick  residences  in  Reno  are  much  improved  by  its  use; 


and  the  new  Elk's  Hall  shows  it  to  advantage.     This  tuff  should 
be  much  used  for  the  demands  befitting  it. 

North  of  Reno :  This  tuff  comes  from  a  mass  of  consolidat- 
ed ash  almost  twenty  miles  northeast  of  Reno,  on  the  Spanish 
Springs  Valley  road.  A  little  stone  has  been  quarried  and  used 
in  Reno  in  ways  similar  to  the  Merrimac  rock.  It's  color  is  a 
light  pink,  a  little  lighter  than  the  first  material.  These  two  stones 
are  very  similar  in  their  features  and  can  be  used  in  precisely  the 
same  ways  and  for  the  same  demands.  This  second  tuff,  howeverr 
is  more  irregular  in  texture,  containing  angular  fragments  of  oth- 
er rocks,  largely  andesite  and  granite,  thereby  appearing  some- 
what mottled  when  closely  inspected.  It  tempers  slightly  better 
that  the  other.  Careful  selection  should  eliminate  the  unsightly 
stone  from  that  quarried.  The  owner  is  Mr.  Wm.  Schrader,  of 
Reno. 

Lovelock :  This  rock  is  located  in  the  hills  to  the  northeast 
of  the  town  of  Lovelock,  on  the  line  of  the  Southern  Pacific 
railroad.  The  point  from  which  it  has  been  obtained  is  about  four 
miles  from  the  station  with  not  a  hard  haul  over  the  distance. 
The  color  is  a  purplish-gray,  of  a  medium  depth  of  tint.  The 
structure  and  texture  are  in  general  the  same  as  in  the  other  tuffs. 
Many  small  fragments  of  volcanic  rocks  are  interspersed  through- 
out the  mass,  and  small  glassy  cystals  of  feldspar  are  quite  noti- 
cible  on  careful  inspection.  The  rock  inclusions  are  dark  gray, 
so  that  a  close  view  exhibits  many  seeming  imperfections  in  grain. 
Used  in  a  building  these  are  not  apparent,  and  the  whole  aspect  is 
a  very  pleasing  one.  The  usual  shade  of  purple  will  give  a  pret- 
ty contrast  with  other  stones  whose  color  blend  with  its,  own. 
The  hardness  and  strength  are  good,  ranking  well  up  with  that  of 
the  best  sandstone,  while  at  the  same  time  it  is  resistant  to  atmos- 
pheric changes.  A  vast  amount  is  in  sight,  and  when  once  intro- 
duced, a  ready  market  should  follow. 

Washoe :  A  rock  similar,  yet  different,  from  the  three  tuffs 
mentioned,  is  found  at  Washoe,  on  the  Virginia  and  Truckee 
railroad.  This  notice  is  of  value  chiefly  from  a  historical  stand- 
point, as  several  of  the  old  abandoned  buildings  of  the  once  thriv- 
ing town  are  made  wholly  of  this  stone.  In  it's  nature  it  is  a 
volcanic  agglomerate,  or  a  consolidated  volcanic  mud, 'and  an 
unusual  material  for  purposes  of  construction,  The  old  quarry 
is  on  the  hillsides  above  the  railroad  track  just  north  of  Washoe 
station,  in  a  surface  cut  only  a  few  feet  in  the  mass.  One  is 
tempted  to  describe  it  as  having  a  mud  color,  this  feature  is  so 


very  inconspicuous.  More  specifically  the  color  is  mottled  light 
and  medium  dark  gray,  and  the  surface  usually  appears  dusty  The 
texture  is  quite  porous.  Nothing  in  the  way  of  definite  substances 
or  minerals  can  be  easily  determined  or  distinguished.  It's  last- 
ing qualities  rank  with  an  average  sandstone,  but  its  strength  is 
less.  It  is  easily  available,  but  its  use  cannot  be  urged  in  the  face 
of  much  more  and  better  stone. 

ATMOSPHERIC  ROCKS 

SANDSTONES 

Nevada  has  had  developed  up  to  the  present  time  only  a  few 
rocks  of  this  family,  and  none  of  them  can  be  called  first-class. 
They  are  all  of  recent  geological  age,  and  owe  their  qualities 
to  their  youth.  As  the  development  of  the  state  goes  on,  more 
such  will  surely  be  found,  perhaps  some  of  the  very  best.  These 
stones  will  be  needed  as  the  cities  and  towns  grow,  and  the  best 
will  command  a  good  price. 

Carson  :  The  first  and  most  important  sandstone  is  the  well 
known  one  at  the  State  Prison,  near  Carson.  The  quarry  consti- 
tutes the  prison  yard,  and  has  had  the  most  work  done  of  any  in 
the  state.  The  sandstone  beds  or  strata  occupy  the  site  of  an  ex- 
tinct lake,  and  exhibit  the  quite  famous  animal  tracks  on  the  pres- 
ent floor.  The  color  is  a  yellowish-gray,  a  gray  unfortunately, 
streaked  with  a  light  yellow,  and  not  uniform.  The  rock  is  rather 
heavily  bedded,  with  the  bedding  planes  nearly  horizontal.  This 
position  is  probably  the  same  one  the  stone  has  always  occupied, 
although  slight  tilting  may  have  occurred.  On  this  account,  of 
horizontality,  quarrying  is  easily  done.  That  mineral  content 
shows  the  stone  to  be  derived  from  the  weathering  and  decom- 
position of  a  granite,  the  yellowish  tinge  being  due  to  the  oxidation 
of  the  iron  bearing  substances.  The  constituent  grains  are  ce- 
mented by  secondary  silica.  The  grain  of  the  rock  is  of  medium 
fineness  in  the  average,  but  at  times  becomes  quite  coarse,  con- 
taining pebbles  up  to  half  and  inch  in  size.  The  hardness  and 
strength  are  medium,  sufficient  for  all  ordinary  needs,  and  the  re- 
sistance to  other  forms  of  change  is  good.  There  is  much  ma- 
terial in  sight  at  the  prison  yard.  The  stone  has  been  used  largely 
in  Carson  and  Reno.  The  new  chemistry  building  at  the  Univer- 
sity is  constructed  wholly  of  it,  and  presents  a  very  satisfactory 
appearance.  A  small  amount  has  found  a  resting  place  in  the 
stone  entrance  to  the  University  grounds,  as  is  shown  in  the  front- 
ispiece. v 


Fall-on  :  This  sandstone  occurs  near  the  town  of  Fallon,  in 
Churchill  county.  Little  quarrying  has  been  done,  but  samples  of 
the  rock  show  its  main  features.  In  color  it  is  a  cream  white  very 
uniform  in  the  small  pieces  shaped  for  exhibition.  The  grain, 
too,  is  uniform,  and  quite  fine.  It's  hardness  and  strength  are 
about  equal  to  those  of  the  Carson  stone,  and  satisfactory.  It 
should  resist  the  weather  well,  and  appear  to  be  a  very  fair  stone 
for  building  purposes.  Mr.  L.  B.  Self,  of  Reno,  is  the  owner. 

Winnemucca:  There  are  two  varieties  of  these  stones  quar- 
ried near  and  used  in  Winnemucca.  Neither  are  first-class  in  any 
respect,  though  they  do  well  enough  for  the  local  uses.  They 
are  taken  from  the  old  lake  beds,  to  the  northeast  of  the  town. 

The  first  stone  is  quarried  nine  miles  from  the  railroad  sta- 
tion and  hauled  in  by  team.  The  color  is  a  light  drab,  and  quite 
uniform.  The  minerals  and  substances  comprising  the  stone  do 
not  show,  on  account  of  the  fineness  of  the  grain.  Some  black 
flakes  of  mica  are  noticible,  but  nothing  else.  The  hardness  and 
strength  are  low,  too  low  for  anything  but  the  smaller  structures 
and  the  uses '  demanding  little  power  to  withstand  pressure  or 
stress.  It  stands  temperature  changes  well,  and  were  its  strength 
higher  would  be  an  admirable  building  stone.  Some  new  build- 
ings have  recently  been  erected  in  Winnemucca  composed  largely 
of  this  stone.  Such  local  uses  are  well  met,  but  the  demand  for 
such  a  rock  will  of  necessity  be  limited  to  the  town  itself.  Mr. 
Joe  Pasquale  is  owner  of  the  stone. 

The  second  variety  of  sandstone  is  quarried  from  a  point  four 
miles  from  the  town,  and  much  more  available.  However,  the 
quarry  has  been  abandoned,  on  account  of  numerous  faults  and 
breaks  in  the  material,  which  render  the  cost  of  obtaining  stone  fit 
for  building  almost  prohibitive.  The  color  is  a  light  gray;  the 
texture  is  coarser  than  in  the  first  variety,  and  somewhat  variable. 
The  hardness  and  strength  are  considerably  more  than  in  the 
first,  so  that  were  the  stone  to  be  easily  obtained  its  use  would  be 
wide.  New  developments  later  may  show  different  and  more 
favorable  conditions.  The  new  fire  company  house  in  Winne- 
mucca shows  a  handsome  front  of  this  material.  Mr.  Pasquale 
is  owner  of  this  stone,  as  of  the  first. 

Elko :  At  Elko  there  is  a  sandstone  much  like  the  first  one 
described  from  Winnemucca.  As  with  the  rest  of  the  soft  ma- 
terials, its  use  is  limited  to  small  buildings,  where  the  strain  upon 
it  is  light.  The  local  demands  are  met  sufficiently  well  by  it,  but 
it  can  never  have  wide  use.  There  is  surelv  much  first  class  build- 


ing  material  to  be  developed  in  this  part  of  the  state  as  the  popula- 
tion increases. 

MARBLE. 

The  marbles  in  Nevada  are  well  represented,  although  little 
has  been  done  to  develop  them.  Only  a  few  are  quarried,  due,  of 
course,  to  the  scattering  demand  and  difficulty  of  gaining  a  market 
against  other  stone  now  used.  It  should  not  be  many  years  before 
a  steady  market  is  open  to  them,  not  only  in  this  state,  but  iln 
others  as  well. 

La  Moille  Valley:  On  the  borders  of  this  valley,  in  Elko 
county,  exists  a  vast  amount  of  a  fairly  good  variety  of  marble. 
No  quarrying  has  ,J^en  done,  but  some  stone  has  been  -taken-  out 
to  show  its  character.  The  color  is  white  in  one  variety,  and  a 
gray,  or  a  laminated  gray  and  white,  in  another.  The  white  is 
clear,  not  marked  by  yellowish  spots  or  flaws.  The  stone  is  rather 
finely  crystalline,  and  takes  a  good  polish.  The  marbles  are  all 
hard,  brittle,  and  easily,  though  slowly,  soluble  in  atmospheric 
waters,  as  has  been  discussed  in  a  previous  chapter.  -  The  rock  is 
not  very  far  from  transportation  facilities,  and  should  meet  with 
some  demand.  The  uses  are  mainly  interior  ones,  such  as  tiling 
for  floors,  mantels,  mosaic  work,  and  others.  Mr.  W.  T.  Crane, 
of  Lee,  Elko  county,  is  the  owner. 

Humboldt  Mountains:  In  these  mountains  a  considerable 
amount  of  coarsely  crystalline  marble  exists,  which  may  prove  of 
some  value  upon  more  careful  investigation.  What  rock  has  been 
seen  shows  a  pure  white  color  with  few  impurities  appearing  on 
weathering.  This  is  not  the  only  place  where  such  rocks  are 
known  to  exist ;  it  is  cited  merely  as  an  instance  of  the  little  knowi- 
edge  regarding  these  things. 

Luning:  More  marble,  of  gray  and  white  colors,  exists  in 
the  region  in  the  vicinity  of  Luning,  Esmeralda  county.  Some  of 
this  has  been  quarried  and  used  by  Mr.  Lindsay,  of  Carson,  and  it 
ranks  with  the  others  mentioned.  It  outcrops  on  the  line  of  the 
Carson  and  Colorado  railroad,  hence  is  easy  of  access,  which  is  a 
strong  point  in  its  favor.  More  facts  concerning  it  are  needed. 

Topaz,  California :  Considerable  marble  is  found  in  Antelope 
Valley,  in  California,  opposite  Douglas  county,  in  this  State.  As 
its  use  and  development  comes  naturally  through  Nevada,  it  needs 
a  mention  here.  The  stone  varies  considerably  in  color,  from  white 
to  blue,  gray,  and  yellow.  As  the  locality  is  off  the  railroad,  the 
development  work  has  lagged,  but  the  rock  deserves  some  atten- 


tion  in  the  near  future.     The  uses  are  those  already  mentioned. 
Mr.  Lindsay,  of  Carson,  owns  much  of  the  material. 

Inyo  County,  California:  Considerable  marble  has  been 
quarried  in  Inyo  county,  California,  and  used  both  in  Nevada  and 
California  for  tiling,  mantels,  mosaic  work,  and  such  demands. 
Some  of  the  rock  is  laminated ;  most  is  not,  but  cracks  and  flaws 
are  quite  common.  There  are  three  distinct  colors  of  the  marble , 
white,  yellowish-white,  and  dark  gray.  The  contrast  between 
these  is  very  pleasing  to  the  eye.  The  lasting  qualities  are  the 
same  as  the  other  stones  of  like  nature  possess.  The  stone  works 
on  the  Truckee  river  above  Verdi  are  handling  this  rock  almost 
entirely  and  have  some  large  contracts  on  hand. 

TRAVERTINE). 

Bridgeport,  California'.  This  variety  of  stone  is  related  to 
the  limestone,  having  been  deposited  by  springs.  A  great  deal  of 
these  deposits  are  to  be  found  over  southeastern  California,  Ne- 
vada, and  Arizona,  marking  the  sites  of  old  springs.  The  only 
occurrence  yet  exploited  in  or  near  Nevada  to  any  extent  is  nelar 
Bridgeport,  in  Mono  county,  California.  The  stone  is  a  variegated 
reddish,  and  yellowish,  very  handsome  when  polished.  It  was 
used  in  the  new  City  Hall  in  San  Francisco.  The  work  of  exploi- 
tation needs  to  be  carried  farther,  as  it  will  be  when  more  demand 
is  made  for  the  material.  Its  uses  are  purely  ornamental. 

It  is  needless  to  say  that  very  many  more  stones  suitable  for 
purposes  of  construction  exist  in  the  State.  Only  those  actually 
used,  and  those  about  ready  to  be  used,  have  been  listed.  There 
are  many  more  known ;  there  are  vast  amounts  to  be  discovered. 

The  frontispeice  shows  a  number  of  the  rocks  mentioned  ac- 
tually in  use  in  the  "University  Gates."  The  large  columns  sup- 
porting the  gates  are  made  from  granite  taken  from  boulders  near 
Reno.  The  smaller  pillars  just  outside  are  composed  of  Washoe 
granite,  a  shade  darker  than  the  first.  The  stone  wall  exhibits 
two  more.  The  first,  or  ground  course  of  blocks  in  the  wall  to  the 
left  is  made  of  the  andesite  from  the  Fulton  quarry,  north  of  Reno. 
The  upper  three  courses  of  stone  are  all  the  Carson  sandstone. 
The  finish  throughout  is  rough,  and  the  appearance  very  pleasing. 


CHAPTER  V. 

ROAD  METAL  AND  SOME  GENERAL  PRINCIPLES  OF  ROAD  MAKING. 

This  subject  does  not  come  strictly  under  the  head  of  building 
stones,  yet  its  vast  importance  to  the  welfare  of  any  community, 
together  with  the  fact  that  some  knowledge  of  rocks  is  essential 
to  a  proper  understanding  of  it,  more  than  justifies  a  short  chapter 
setting  forth  a  few  fundamental  considerations.  The  bicycle  and 
other  horseless  vehicles  have  done  one  great  work,  if  nothing  else ; 
they  have  shown  conclusively  to  all  people  the  value  and  immense 
importance  of  good  roads. 

Time  was  when  the  old  earth  road  was  held  sufficient  for  all 
needs,  and  such  roads  were  not  even  crowned.  We  still  have  many 
earth  roads,  which,  when  properly  compacted  and  graded,  do  well 
enough  for  light  traffic  in  sparcely  settled  regions.  Where  travel 
is  at  all  heavy,  however,  earth  roads  become  a  makeshift,  and 
some  material  which  will  not  cut  to  pieces  is  needed.  Very  natur- 
ally, men  have  turned  to  rocks  to  furnish  such  material,  termed  in 
general,  "road  metal."  The  roads  made  by  crushed  rock  on  an 
earth  foundation  are  called  macadam,  from  the  name  of  the  man 
who  introduced  them. 

For  the  purposes  of  road  construction  we  have  a  vast  abun- 
dance of  rocks  of  various  kinds  and  character.  Bearing  in  mind 
the  classification  of  rocks  in  Chapter  II,  we  realize  the  range  of 
choice.  All  of  the  igneous,  atmospheric  and  metamorphic  rocks, 
of  hardness  greater  than  earth,  might  be  used.  By  clas£  the 
igneous  rocks  are  hardest,  the  atmospheric,  softest;  the 
igneous  are  more  or  less  crystalline,  the  atmospheric  large- 
ly fragmental.  The  metamorphic  rocks  are  intermediate  in 
their  qualities.  In  Nevada  there  is  a  large  development  of  all 
these  kinds,  easy  of  access.  But  this  wide  range  of  choice  not 
only  furnishes  abundant  possibilities,  but  also  allows  the  selection 
of  the  best.  It  must  be  self-evident  that  all  road  materials  are  not 
of  equal,  nor  anywhere  near  equal  value.  There  is  always  a  best 
and  a  poorest  for  every  case.  In  order  to  select  the  best  road 
metal  for  a  certain  street  or  road,  a  knowledge  of  the  principles 
underlying  such  choice  must  be  had.  A  brief  account  of  these  will 
be  presented. 

The  fundamental  fact  on  which  all  road  making  is  clone  is 
the  simple  one  that  a  highway  is  constructed  to  withstand  constant 
wear.  It  must  first  be  known,  therefore,  of  what  this  wear  con- 
sists. The  wasting  of  a  road  is  due,  first,  to  chemical  agencies; 
second,  to  physical  agencies  ;  and,  third,  to  mechanical  agencies. 


The  chemical  agencies  are  those  constantly  at  work  in  the  atmos- 
phere, and  producing  (i)  solution  and  (2)  decomposition,  as, 
pointed  out  under  building  stones.  The  physical  agents  are  like- 
wise atmospheric,  and  are:  (i)  frost,  producing  disruption  of 
the  road  and  of  the  individual  rock  fragments;  (2)  the  effects  of 
rain  falling  on  the  surface,  running  off,  loosening  the  road  sur- 
face and  transporting  the  material  away;  (3)  the  wearing  effects 
of  the  wind  in  carrying  off  the  fine  particles  as  dust.  The  mechan- 
ical agencies  are  due  to  the  action  of  living  things ;  the  wearing 
down  and  grinding  up  of  the  surface ;  the  crushing  effect  of  heavy 
•loads  and  impact  of  of  the  feet  of  animals;  and  the  possible  injur- 
ious effects  of  roots.  With  roads  properly  constructed,  of  those 
forces  tending  to  impair  their  usefulness  the  physical  and  mechan- 
ical agnets  are  most  important. 

Enough  has  been  written  of  chemical  agencies  under  a  pre- 
vious head,  so  that  a  mere  mention  is  all  that  is  here  necessary. 
Such  processes  in  nature  are  so  slow  that  roads  suffer  little  com- 
paratively from  them.  However,  chemical  reactions  play  an  im- 
portant part  in  the  process  of  compacting,  or  binding  a  road  bed 
and  making  it  durable.  This  power  of  binding,  or  cementing,  in 
a  road  metal,  is  an  essential  quality,  and  the  higher  it  is  the  better. 
All  other  things  being  equal,  the  ideal  road  material  is  that  one 
which  will  furnish  a  large  percentage  of  mineral,  or  minerals,  that 
do  not  alter  or  which  change  very  slowly,  with  some  other  mineral 
or  minerals  capable  of  furnishing,  by  slight  decomposition,  suffi- 
cient cementing  substance  to  bind  the  whole  together  as  a  solid 
mass.  The  particular  minerals  best  fitted  to  accomplish  this  end 
are  those  containing  iron  and  alumina,  with  silica.  Lime  bearing 
minerals  also  are  valuable.  By  way  of  a  homely  illustration,  this 
process  may  be  likened  to  a  sidewalk  made  of  nails,  which,  on 
being  allowed  to  remain  for  some  time,  becomes  rusted  into  a 
solid  condition.  There  are  several  more  important  binding  mate- 
rials, as  clay,  secondary  iron  minerals,  calcite  or  lime,  and  some- 
times silica.  These  must  form,  in  order  to  be  of  greatest  good, 
in  just  the  right  amount  to  bind  the  gradually  pulverized  surface 
coating,  as  well  as  to  harden  the  whole. 

Of  the  physical  agencies,  in  regions  of  considerable  range 
of  temperature,  the  action  of  frost  may  be  of  some  moment.  As 
mentioned  under  rock  weathering,  water,  entering  the  pores  of 
a  stone  and  in  cracks,  on  freezing  becomes  a  powerful  lever  tend- 
ing to  disrupt  the  material.  Also,  the  mere  alternate  cooling  and 
warming  by  daily  variation,  gradually  weakens  a  rock.  In  mild 
climates  these  things  play  no  part.  The  effect  of  rain  in  loosen- 


ing  and  wearing  away  the  road  surface  may  become  a  source  of 
danger  in  poorly  constructed  highways.  The  greater  effect  of 
rain  is  its  power  of  transporting  the  layer  of  fine  material  neces- 
sary on  every  well  kept  road.  This  action  is  measured  by  the 
specific  gravity  of  the  minerals  composing  the  rock  surface,  their 
shape,  and  their  state  of  compactness.  For  instance,  mica  is  a 
poor  miner  to  have  in  a  road  metal,  because  of  its  flaky  nature 
which  allows  of  its  easy  transportation  by  the  rain  and  wind. 
The  selection  of  a  stone  must  consider  all  these  points.  In  like 
manner  the  winds  are  constantly  picking  up  and  carrying  off  as 
dust  the  lightest  rock  flour  from  the  surface,  often  sweeping  the 
streets  clean  of  loose  fragments  and  depositing  dust  over  nearby 
houses  and  vegetation.  Thus,  the  rain  and  wind,  together  or 
singly,  are  mainly  responsible  for  the  loss  of  that  layer  of  finely 
ground  rock  which  should  constantly  cover  the  top  of  every  road 
and  street  a  small  fraction  of  an  inch  in  thickness. 

The  mechanical  agencies  are  the  most  easily  s,een,  and  are 
chiefly  the  grinding  and  pounding  of  the  travel  over  the  high- 
ways, The  pulverized  surface  is  thereby  constantly  loosened 
ready  for  the  wind  or  rain,  and  just  as  fast  as  this  disappears  more 
is  worn  from  the  underlying  rocks  to  replace  it.  Also,  if  the  mass 
of  the  road  be  not  well  compacted,  it  will  loosen,  tending  to  form 
"chuck  holes."  Obviously,  the  heaviest  traffic  will  do  the  most 
damage,  and  will  be  the  most  difficult  to  meet.  The  disrupting 
effect  of  roots  should  be  reduced  to  nothing  by  a  proper  construc- 
tion of  the  road  bed. 

Keeping  these  considerations  in  mind,  it  can  be  seen  that  a 
choice  of  road  metal  is  made  by  considering  for  every  case  ( I )  the 
requirements  which  the  road  must  fulfill;  and  (2)  the  power  of 
given  materials  to  meet  these  conditions.  In  any  one  locality  the 
mechanical  wear  and  tear  is  all  that  varies  appreciably,  the  rest 
remaining  practically  constant.  In  other  words,  the  traffic  changes 
from  place  to  place,  so  that  we  need  harder  and  firmer  highways 
in  a  city  than  in  the  open  country.  These  five  divisions  of  traffic 
are  commonly  made  to  denote  this:  City  (perurban),  urban, 
suburban>  highway,  and  country  road.  City  traffic  is  that  existing 
on  the  streets  of  large  cities,  and  no  ordinary  macadam  can  with- 
stand it.  Stone  and  wooden  blocks,  asphaltum,  vitrified  brick,  and 
some  few  other  substances  are  commonly  used.  Urban  traffic  is 
that  common  to  city  streets  not  used  for  continuous  heavy  team- 
ing. The  hardest  and  toughest  macadam  must  be  used,  for  the 
wear  is  heavy.  Suburban  traffic  is,  as  the  name  denotes,  that 
found  on  city  streets  in  their  outer  limits,  and  in  the  main  thor- 


oughfares  of  country  towns.  A  rock  of  less  hardness  and  tough- 
ness is  required.  Highway  traffic  is  that  found  on  the  main  coun- 
try roads,  for  which  a  material  of  medium  qualities  should  be 
used.  Country  road  traffic  exists  on  the  less  used  roads  in  the 
least  settled  districts.  A  comparatively  soft  rock  is  needed  in  these 
localities.  This  division  of  traffic  is  purely  arbitrary,  yet  of  the 
greatest  importance.  At  first  thought  it  might  appear  that  a  rock- 
well  fitted  for  the  heaviest  traffic  would  surely  be  satisfactory  for 
lighter  travel.  No  greater  mistake  could  be  made.  The  two  op- 
posed forces :  the  wear  on  a  road,  and  the  hardness,  toughness 
and  binding  power  of  the  material  used,  giving  resistance  to 
wear,  must  actually  balance  each  other  to  give  the  highest  results 
in  any  given  case.  The  road  surface,  composed  of  the  necessary 
layer  of  fine  material,  must  be  renewed  just  as  fast  as  it  disap- 
pears. In  other  words,  speaking  broadly,  as  fast  as  the  wind  and 
water  carry  away  the  materials  from  the  top  of  a  road,  just  so  fast 
should  the  under  rock  fragments  grind  down  under  travel  to 
form  new  surfacing.  The  amount  of  work  done  by  the  wind  and 
water  should  be  reduced  to  a  minimum  by  selecting  a  road  metal 
with  maximum  binding  quality.  Then  the  other  qualities  of  the 
stone  must  be  fitted  to  the  needs  of  the  travel  destined  to  be  over 
it.  If  too  small  a  supply  of  fine  surface  material,  or  "binder,"  be 
furnished,  because  of  too  light  traffic  for  the  particular  stone  used, 
the  road  "ravels,"  and  the  underlying  rock  fragments  project, 
making  the  road  rough  as  well  as  weak.  If  too  much  protecting 
surface  be  supplied,  from  too  heavy  traffic,  the  excess  results  in 
dust  or  mud.  In  a  moist  climate  a  thicker  layer  of  surfacing  is 
permissable  than  in  a  dry  climate. 

Having  these  few  fundamental  considerations  in  mind,  it  is 
possible  to  choose  a  road  metal  with  greater  chances  of  its  success. 
The  three  main  characteristics  which  must  be  considered  first  are 
hardness,  toughness,  and  binding  power.  Hardness  is  the  resist- 
ance of  a  rock  or  mineral  to  rubbing,  as  by  grinding  on  an  emery 
wheel,  and  to  force  applied  to  crush  the  stone.  Toughness  is  thq 
resistance  to  fracture  by  blows,  as  continually  delivered  upon  a 
road  by  travel.  The  cementing  power  has  been  explained  as  due 
to  slight  chemical  change  in  the  rock.  It  is  also  due,  in  small 
part,  to  the  mere  presence  of  a  little  moisture.  It  is  well  krfbwn 
how  firm  wet  sand  is  compared  to  dry.  In  all  cases,  a  slight  per- 
centage of  water  in  the  mass  of  road  material  is  necessary.  There 
is,  naturally,  much  diversity  of  opinion  regarding  the  values  of 
the  various  road  materials.  A  rock  suitable  in  all  respects  for  one 
locality  may  easily  prove  a  total  failure  in  another.  A  stone  much 


affected  by  frost  should  not  be  used  in  a  cold  region,  nor  will  a 
brittle  one  give  the  best  results  in  a  dry  climate.  It  appears  to  be 
the  consensus  of  opinion  that,  all  things  considered  those  rocks 
called  popularly  "traps"  are  the  best.  These  rocks  are  found 
typically  as  dykes,  hence  are  intermediate  in  texture,  and  are 
largely  diabase  and  diorite.  They  are  among  the  toughest  of  the 
rocks,  and  usually  have  good  binding  power.  The  best  varieties 
of  these  traps  make  satisfactory  roads  for  urban  traffic,  but  are 
too  hard  and  tough  for  the  lighter  travel.  The  finer  grained 
plutonic  rocks  probably  come  next  in  order  of  value,  the  more 
basic  being  the  best  as  a  rule,  because  of  better  cementing  qualities. 
Granite  is  often  frowned  upon,  yet  some  granites  have  given  good 
results.  The  presence  of  hard,  but  brittle,  quartz  seems  to  be  the 
chief  objection,  while  micaceous  granites,  as  well  as  all  rocks  con- 
taining mica,  are  unsatisfactory.  However,  given  a  binding 
power  in  a  stone,  any  ordinary  amount  of  free  quartz  is  of  real 
value,  because  it  is  not  decomposed  under  ordinary  conditions, 
and  furnishes  an  unchanging  base  for  the  road.  The  volcanic 
rocks  are  of  varying  values.  Basalt  blocks  are  used  for  paving 
for  city  traffic,  but  for  macadam  their  field  is  limited.  Preference 
is  given  the  crystalline  rocks.  Rhyolites,  with  sufficient  binding 
power,  have  given  excellent  results  in  some  localities.  Andesites 
might  also  make  good  roads.  The  crystalline  metamorphic  rocks, 
the  gneisses  and  schists  have  been  uajed  with  good  results.  Of 
the  atmospheric  rocks,  few  seem  to  find  favor.  In  the  West,  es- 
pecially in  California,  such  rocks  have  been  largely  used,  with 
eminent  success.  In  Golden  Gate  Park,  San  Francisco,  a  dark  red 
chert  has  furnished  material  for  the  excellent  roads,  which  are 
among  the  finest  in  the  State.  At  other  points  around  San  Fran- 
cisco bay,  and  in  the  interior  valleys,  where  the  climate  is  much 
like  that  of  western  Nevada,  a  metamorphic  sandstone  has  made 
fine  roads.  Also,  a  dark  basic  diorite  has  been  used  for  heavy 
traffic  with  satisfactory  results.  Limestone  would  seem  on  the 
face  of  the  matter  to  be  almost  worthless  as  a  road  metal,  yet  some 
roads  have  been  constructed  of  it  in  the  east  with  great  satisfac- 
tion. Some  varieties^  are  hygroscopic,  that  is,  attract  moisture 
from  the  air  and  might  prove  of  service  in  a  dry  climate.  Here 
in  Nevada,  and  particularly  near  Reno,  where  the  construction  of 
stone  roads  will  begin,  there  are  several  promising  rocks.  An 
immense  supply  of  rhyolite  containing  considerable  iron  outcrops 
less  than  a  mile  north  of  Reno,  and  an  abundance  of  a  medium 
basic  granite,  much  of  it  without  mica,  or  with  little,  exists  to  the 
south  and  west.  The  latter  rock,  considering  the  traffic,  might 


easily  prove  a  success.  Andesite  and  basalt,  of  unknown  value, 
are  also  near  by.  The  reddish  andesite  used  in  the  Carnegie 
Library  should  make  an  excellent  material  for  light  travel.  More 
rock  of  a  similar  nature  is  to  be  obtained  in  abundance  at  Huf- 
faker's,  on  the  line  of  the  V.  &  T.  railroad.  The  diorite  of  Mt. 
Davidson,  and  much  of  the  unaltered  rock  extracted  in  the  mines, 
should  make  a  satisfactory  rock  for  heavy  traffic.  Crystalline 
limestone,  or  marble,  occurs  in  large  amount  in  the  eastern  part 
of  the  state,  as  do  many  other  desirable  rocks  for  road  metal. 
The  possible  value  of  lime  rocks  for  road  purposes  in  this  dry 
climate  has  already  been  mentioned. 

But  in  spite  of  these  few  general  principles,  and  list  of  pos- 
sible materials,  there  comes  the  one  question  "will  such  and  such 
a  stone  be  a  success?"  We  are  apparently  confronted  by  the 
truth  of  the  old  maxim  "the  proof  of  the  pudding  is  in  the  eating." 
Very  fortunately,  however,  we  are  not  driven  to  the  necessity  of 
actually  constructing  roads  merely  to  test  certain  materials.  The 
application  of  general  principles  to  measurements  of  the  various 
qualities  of  a  rock  not  on  a  road  building  scale  will  tell  almost 
everything  needed  in  the  way  of  information.  Laboratories  for 
the  testing  of  road  materials  have  been  installed  at  several  places 
in  the  United  States.  The  two  of  particular  value  to  Nevada  are 
the  laboratories  at  the  University  of  California  and  at  Washington, 
D.  C.,  under  the  Department  of  Agriculture.  In  the  latter  case, 
any  person  may  have  a  full  test  made  of  a  rock  for  road  construc- 
tion free  of  charge,  the  only  expense  being  that  of  freight  charges 
on  the  railroad.  Requests  for  blank  forms  and  instructions  should 
be  addressed  to  the  Road  Materials  Laboratory,  Office  of  Road 
Inquiry,  Department  of  Agriculture,  Washington,  D.  C.  Full 
tests  are  made,  and  the  fitness  of  a  stone  for  road  material  is  given 
in  detail.  The  laboratories  at  the  University  of  Nevada  are  poorly 
equipped  to  make  more  than  a  few  simple  tests,  for  special  appara- 
tus is  required.  Considerable  aid  can  and  will  be  given  to  interested 
parties,  however. 

Although  much  in  the  way  of  principles  underlying  success 
in  road  construction  have  thus  far  been  given,  the  most  important 
condition  of  all  has  been  assumed  complied  with,  namely  that  the 
road  be  properly  constructed.  It  lies  beyond  the  scope  of  these 
few  notes  to  enter  upon  the  engineering  side  of  road  construction, 
and  it  is  only  urged  upon  the  citizens  of  Nevada  to  inform  them- 
selves before  commencing  the  building  of  stone  roads.  A  perusal 
of  the  few  references  given  at  the  end  of  the  chapter  will  furnish 
all  the  facts  necessary,  and  every  voter  should  be  acquainted  with 


them.  Macadam  roads  cost  from  $4,000  to  $10,000  a  mile,  and 
an  error  in  construction  or  judgment  in  selecting  suitable  material 
may  mean  great  loss  to  a  community. 

There  are  two  more  materials  which  deserve  serious  con- 
sideration used  in  constructing  roads.  The  first,  and  perhaps 
of  little  adaptability  or  value  to  most  of  Nevada,  is  vitrified 
paving  brick,  laid  like  ordinary  basalt  blocks  in  a  road.  Roads 
of  this  nature  have  proved  very  efficient  in  the  esat,  especially  in 
the  prairie  States,  and  may  prove  of  value  elsewhere.  A  reference 
covering  the  subject  is  given.  The  second  material  is  of  the 
greatest  value  and  adaptability  to  Nevada,  with  her  dry  climate. 
The  unqualified  and  immense  success  of  oil  on  roads,  laying  all 
dust  and  making  a  surface  as  smooth  as  asphaltum,  recommends 
it  as  a  possible  boon  to  this  section  of  the  country,  where  water  is 
scarce.  When  properly  used,  its  success  has  always  been  immedi- 
ate and  great,  and  the  consideration  of  its  use  is  earnestly  urged 
upon  the  citizens  of  this  state.  Its  cost  is  nominal,  and  is  partially 
compensated  by  the  decrease  in  the  cost  of  watering  the  streets 
treated.  Some  of  the  sandiest  and  dustiest  roads  in  southern 
California  have  been  made  into  perfect  highways  by  its  use,  the 
result  being  much  like  a  bituminized  rock  surface. 

The  following  list  of  references  will  be  found  useful  to  all 
those  interested.  They  may  be  obtained  free  of  cost  by  applying 
to  the  Secretary  of  Agriculture,  Washington,  or  at  the  Experi- 
ment Station  at  the  University  of  Nevada. 

(i.)  "The  Forces  Which  Operate  to  Destroy  Roads,  With 
Notes  on  Road  Stones  and  Problems  Therewith  Connected."  Cir- 
cular No.  29.  Office  of  Road  Inquiry,  U.  S.  Dept.  of  Agric. 

(2.)  "The  Selection  of  Materials  for  Macadam  Roads.'' 
Yearbook  of  Dept.  of  Agric.,  1900. 

(3.)  "Historical  and  Technical  Papers  on  Road  Building  in 
the  United  States."  Bull.  No.  17.  Office  of  Road  Inquiry. 

(4.)  "The  Testing  of  Road  Materials.'"  Bull.  No.  79.  Bu- 
reau of  Chemistry,  Dept.  of  Agric. 

(5.)  "Methods  of  Constructing  Macadamised1  Roads."  Cir- 
cular No.  21.  Office  of  Road  Inquiry. 

(6.)  "Highway  Repairing."  Circular  No.  24.  Office  of 
Road  Inquiry. 

(7.)  "Brick  Paving  for  Country  Roads."  Circular  No.  25. 
Office  of  Road  Inquiry. 


(8.)   "Earth  Roads."     Farmers'  Bulletin  No.  136.     Dept.  of 
Agric. 

(9.)   "The  Use  of  Oil  on  Roads."     Year  book  of  Dept.  of 
Agric.,  1902. 

(10.)   "The  Social,  Commercial  and  Economic  Phases  of  the 
Road  Subject."    Circular  No.  34.    Office  of  Road  Inquiry. 

(n.)   "Going  in  Debt  for  Good  Roads."     Circular  No.  26. 
Office  of  Road  Inquiry. 

(12.)   "Wide  Tires."    Bull.  No.  12.    Office  of  Road  Inquiry. 


CHAPTER  VI. 

CONCLUSION. 

There  are  a  few  points  to  be  emphasized  and  a  few  explained 
before  bringing  this  paper  to  a  close.  The  real  need  of  such  pub- 
lications, incomplete  as  they  must  necessarily  be  in  a  new  and 
undeveloped  State  like  Nevada,  is  surely  apparent  to  all  pro- 
gressive citizens.  The  vast  size  of  the  unknown  and  undeveloped 
in  the  State  is  almost  appalling  when  contrasted  with  what  little 
is  known.  And  the  work  of  the  future,  the  proper  opening  up  of 
the  State  in  all  possible  ways,  depends  largely  upon  the  methods 
of  its  accomplishment.  The  haphazard  stage  has  been  passed, 
and  we  must  build  solidly  and  scientifically.  The  bonanzas  have 
been  exhausted  from  the  great  Comstock,  and  the  future  of  that 
famous  lode  rests  upon  the  scientific  mode  of  attacking  the  prob- 
lem now  present :  that  of  working  immense  bodies  of  low-grade 
ore  at  a  profit.  And  with  the  agriculture  of  the  State,  that  indus- 
try which  heretofore  lagged  behind  the  rest,  the  great  problems 
of  irrigation  are  fundamentally  connected.  Every  detail  must  be 
worked  out  scientifically,  in  accordance  with  law  and  order. 
Likewise  with  the  building  stones  of  Nevada.  No  order,  and  little 
real  knowledge  has  governed  the  choice  and  use  of  materials  in 
the  past.  No  harm  has  been  done,  because  the  needs  were  few 
and  simple.  But  with  the  growth  of  large  towns  and  cities,  new 
and  great  buildings  will  be  required,  and  real  scientific  facts  about 
the  materials  of  construction  available  will  be  needed.  And  so 
with  many  other  lines  of  human  activity.  We  need  not  only  to 
know,  but  to  know  in  the  right  way ;  to  have  scientific  knowledge, 
to  understand  law  and  truth.  It  is  largely  to  aid  in  bringing  about 
the  acceptance  of  such  considerations  that  this  paper  has  been 
written. 

Regarding  the  subject  matter,  a  few  words  of  explanation 
seem  necessary.  First,  the  rock  classification  may  strike  petro- 
raphers  as  rather  behind  the  times.  It  is,  and  necessarily  so.  The 
tendency  of  modern  petrographic  thought  ts  toward  the  drawing 
of  fine  lines,  and  the  classification  of  rocks  in  accordance  with  new 
ideas  and  conceptions.  This  is  all  necessary  and  right,  but  the 
unitiated  have  no  use  for  such  terms  as  "persalane,"  "dofemic,"' 
and  the  rest.  A  popular  terminology  will  and  must  always  be 
distinct  from  the  petrographic,  if  such  names  are  universally 
adopted  by  scientists.  The  main  idea  underlying  the  writing  of 
the  chapter  on  the  classification  of  rocks  is  this:  To 
convev  some  definite  idea  to  the  practical  man  re- 


garding  the  meaning  of  the  general  names  of  rocks,  with 
the  characteristics  appertaining  thereto  .  Very  unfortunately,  it 
seems  to  the  writer,  that  with  the  advent  of  more  exact  petro- 
graphic  nomenclature  must  come  more  or  less  of  a  dual  classifica- 
tion of  rocks.  The  old  terms  are  good  and  sufficient  for  all  prac- 
tical needs,  and  need  no  change  for  these  purposes,  no 
matter  to  what  lengths  the  more  exact  terminology 
may  go.  Moreover,  they  cannot  be  changed,  for  obvious 
reasons,  and  this  must  not  be  forgotten  by  the  scientist  in  his 
search  after  truth. 

The  chapter  on  the  qualities  of  building  stones  is  complete 
enough  for  the  purposes  of  the  present  paper  but  will  need  more 
details  for  a  larger  report.  The  larger  facts  are,  of  course,  given 
in  full.  Amplification  of  the  methods  of  testing  building  ma- 
terials is  likewise  needed  when  a  final  report  is  issued. 

Regarding  the  rocks  themselves,  the  list  brings  to  light  some 
important  facts.  It  is  to  be  seen  that  at  present  some  amounts 
of  stone  are  used,  and  that  this  use  is  daily  increasing.  Also  it 
is  stated  with  the  awakening  of  the  State  to  new  and  better  times, 
a  great  increase  in  stone  buildings  will  occur.  But  the  cardinal 
point  is  this:  So  very  little  is  known  definitely  about  Nevada; 
the  welfare  of  the  State  depends  largely  upon  this  knowledge  of 
her  resources,  not  only  in  the  one  small  line  of  building  stones, 
but  in  all  the  ways  of  human  activity.  This  thought  should  not 
be  lost  sight  of  for  an  instant. 

The  chapter  on  road  metal  is  included  because  it  is  believed 
to  fill  a  real  need  for  information.  Reno  must  soon  lay  new  streets 
to  meet  the  demands  of  an  increasing  population,  and  it  will  not 
be  long  before  some  of  the  other  large  towns  follow  suit.  And 
road  construction,  like  many  other  engineering  works,  looks  easy 
to  the  uninstructed.  To  the  business  man,  mining  appears 
to  consist  of  digging  a  hole  and  taking  out  ore.  Likewise  to  the 
same  ordinary  man  of  business,  road  making  seems  to  consist 
merely  of  dumping  a  lot  of  rock  on  a  road  and  smoothing  it  off  a 
bit.  Both  ideas  are  greatly  in  error,  and  it  is  high  time  every  good 
citizen  knew  something  of  the  proper  construction  of  roads.  And 
it  is  to  be  remembered  that  it  is  not  always,  nor  often,  that  the 
street  which  costs  the  least  to  construct  is  the  cheapest. 

Lastly,  it  is  to  be  stated  that  all  in  his  short  paper  has  been 
written  in  the  dawn  of  the  light  coming  from  the  new  day  of 
prosperity  for  the  State  of  Nevada,  with  her  boundless  wealth  of 
material  things  just  beginning  to  awaken  due  appreciation. 


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